Product Hierarchy Research Articles

Decision Aids for the Management of Large Non-Job Shop Type Manufacturing Systems

In this paper we examine the problems of management and control of large scale multi-product multi-line batch manufacturing outside the mechanical engineering industries. The main examples of such non-job shop type manufacturing arises in the making of frequently purchased products e.g. small consumer goods, processed foods, cigarettes, candy, etc. The decision making problems which arise in such systems are extremely complex and the decision support tools for helping management at various levels could be of significant advantage in improving the productivity of such businesses. This paper describes a number of decision support tools which could be used at the different levels of the production hierarchy.The production hierarchy in virtually all manufacturing can be conveniently divided into 4 levels each of which is characterised by a significantly different time scale from that of the other levels. At the highest level, the time horizon of interest is 1 to 5 years and the decision making is of a strategic nature. At the next level down where the time horizon of interest is from 1-2 months to 1 year, the decision making is operational/tactical. The third level down concentrates on issues of production planning and scheduling and its horizon of interest varies from 1 hour to about 20 weeks. The lowest level deals with disturbances occurring over a very short horizon (a few seconds to about 1 hour) and at this level, most of the decision making is automatic (PID controllers, optimal control, self tuning regulators, etc.). Each higher level provides performance targets for the next level down.In this paper we examine the main issues which arise at the top three levels in the hierarchy and describe some decision support tools which have been developed by the author and others. At the top two levels the tools are designed to cope with the issues of competition whilst at the lower level (production planning and scheduling) the problems of allocating tasks to limited resources in the most cost effective way are addressed. Overall, we show how improved efficiency at each level can lead to significant improvements in productivity.

Brésil : modernisation agricole et restructuration alimentaire dans la crise internationale

This study examines the complex relationship of capital accumulation, external debt, and food supply in Brazil, a country which has simultaneously increased its food exports and its unsatisfied demand for food imports in the context of the world economic crisis. In Brazil, the substitution of export cash crops for subsistence crops has been accompanied by a profound but incomplete restructuring of the basic food supply and model of consumption, a restructuring made possible by declining real cost of the new foods. The gap between the extremely rapid evolution of consumption, especially in the urban areas, and the possibilities of concomitant transformation of production is the characteristic feature of the change occuring in Brazil. The current diet of the developed countries evolved over a relatively long period and was based on the declining real cost of basic foodstuffs made possible by increasing labor productivity. Between 1800-1900, the real cost of a kilo of bread was halved, while that of meat remained stable. In France and the US respectively, 80 and 90% of the principal cereals are consumed by animals, while in developing countries most grains are directly consumed. Numerous indices suggest that Brazil has begun to differentiate its food regime in the direction of decreased consumption of cereals, tubers, and legumes, and increased consumption of animal products, with grains increasingly consumed indirectly by animals. Since the early 1970s, Brazil has developed a powerful processed food industry which supports intensive breeding of poultry and, to a lesser extent, pork and milk cattle. However, low income population groups have been forced to reduce their consumption of traditional foodstuffs, whose real prices have undergone relative increases, without achieving a satisfactory level of consumption of the new products. Brazilian food problems result not from insufficient production of food but from the choice of a strongly internationalist model of development in the mid-1960s which required insertion into the world economy, notably through a search for new export sectors. The agricultural sector was assigned 3 functions: producing food as cheaply as possible, increasing the proportion of exportable crops, and substituting some of the foods imported. Brazil evolved in 2 decades from a classic agroexporter to a more complex structure reflecting the semiindustrialized state of the economy. The share of processed agricultural goods increased accordingly. The foods produced for the internal market have been changing at the same time that a new hierarchy of exportable products has evolved. Agricultural policy involved recourse to market mechanisms and cheap credit focused on the south and southeastern regions, large and medium sized producers, and a few products including soy, coffee, sugar cane, and cotton. Just 3% of credits went to the traditional foodstuffs beans and manioc. The most serious consequence of the internationalization of the agricultural economy has been a dangerous increase in the vulnerability of low income groups to world food price fluctuations.

Factors affecting survivorship, growth, and fruit production in a beach population of Xanthium strumarium

In a beach population of Xanthium strumarium, we assessed the effects of density, seedling emergence date, and soil moisture on seedling survivorship, plant growth, and fruit production. Seedling survival was largely density independent, while growth and fruit production declined significantly with increased density. Delayed seedling emergence resulted in significantly lowered survival but exhibited no significant effects on fruit production. Soil moisture was correlated positively with seedling survival, growth, and fruit production. Blowing sand was noted as an important cause of seedling mortality. Increased survival in areas of high soil moisture apparently resulted because of an absence of blowing sand in these areas. Consistent with a lack of density-dependent mortality, the density–yield relationship for the population had a slope near −1 and not −3/2. Hierarchy in fruit production among plants was least developed in areas of high plant density.

Quaternion quantum mechanics: Second quantization and gauge fields

Recent work on algebraic chromodynamics has indicated the importance of a systematic study of quaternion structures in quantum mechanics. A quaternionic Hilbert module, a closed linear vector space with many of the properties of a Hilbert space is studied. The propositional system formed by the subspaces of such a space satisfy the axioms of quantum theory. There is a hierarchy of scalar products and linear operators, defined in correspondence with the types of closed subspaces (with real, complex or quaternion linearity). Real, complex, and quaternion linear projection operators are constructed, and their application to the definition of quantum states is discussed. A quaternion linear momentum operator is defined as the generator of translations, and a complete description of the Euclidean symmetries is obtained. Tensor products of quaternion modules are constructed which preserve complex linearity. Annihilation-creation operators are constructed, corresponding to the second quantization of the quaternion quantum theory with Bose-Einstein or Fermi-Dirac statistics. The tensor product spaces provide representations for algebras with dimensionality increasing with particle number. The algebraic structure of the gauge fields associated with these algebras is precisely that of the semi-classical fields introduced by Adler.

The Household and Class Formation: Determinants of Residential Location in Ciudad Juaréz

An increasing number of jobs in the Ciudad Juárez-El Paso region is directly attributable to the growth of export-oriented manufacturing activity. These jobs, particularly those in Ciudad Juarez, tend to be at the bottom of the production hierarchy, low-skilled, and impermanent. Sectoral diversification in the regional labor market is being accompanied by homogenization of skills required for available jobs. Analysis of a survey of 1236 households in Ciudad Juárez indicates how they are responding to the changing character of labor demand. The households most directly affected by the industrialization process, those of the maquiladora or assembly-plant work force, arc compared with other types of households in the city. In addition, determinants of income in spatial sectors of the city are analyzed.

T cell regulation of immunoglobulin class expression in the antibody response to trinitrophenyl-ficoll. Evidence for T cell enhancement of the immunoglobulin class switch.

In the absence of T cells, B cells were found to respond to the type 2 T-independent (TI-2) antigen, trinitrophenyl (TNP)-Ficoll, with a characteristic hierarchy of IgM and IgG subclass Ab production which directly correlated with 5' to 3' Igh-C gene order, i.e., IgM greater tha IgG3 greater than IgG1 greater than IgG2b greater than IgG2a. This was evident when immune serum Ab titers were analyzed, when in vitro secretion of antibody from immune cells was measured and when TNP-Ficoll-stimulated clones in a splenic focus assay were analyzed for isotype production. T cells were found to cause a preferential relative increase in the amount of IgG2a antibody produced to TNP-Ficoll. The T cell responsible was present in anti-IgM neonatally suppressed mice and was needed early in the response, i.e., on the day of immunization or earlier. T cells were found to increase the frequency of TNP-Ficoll-responsive B cell clones that produced IgG2a in the splenic focus assay. The great majority of these IgG2a-positive clones also produced IgM and all or nearly all of the IgG isotypes whose genes are encoded 5' to the Igh-gamma 2a gene. The data are discussed in terms to T cell enhancement of IgG2a Ab synthesis being mediated through T cell enhancement of the Igh-C gene switching mechanism within TNP-Ficoll-responsive B cell clones. Thus, isotypes encoded by genes on the 3' end of the Igh-gamma gene complex, which in the absence of T cells have a low probability of being switched to, are the most influenced by T cell help.

Roles of Consumer and Psychology in Consumer Psychology

An argument is presented for incorporating formally and explicitly the study of consumer behavior in the graduate training program. Consumer psychology is defined and its relationships with other branches of psychology are indicated. Illustrative consumer research problems are proposed, including the criteria of advertising and communications effectiveness, the psychological parameters of taste and offensiveness, and investigations dealing with product hierarchies.