Characteristics Of Production Systems Research Articles

Risk factors associated with pleuritis and cranio-ventral pulmonary consolidation in slaughter-aged pigs

Examination of lung lesions at the slaughterhouse is a useful tool to estimate the importance of respiratory disease at farm, regional or national level. The objective of the present work was to describe the prevalence of gross lung lesions at slaughter, with a special focus on pleuritis and cranio-ventral pulmonary consolidation, and to identify major risk factors for these lesions. Data from 107 farms involving approximately 11,000 pigs enabled gross lung lesions to be correlated with serology to different swine respiratory pathogens as well as with production system characteristics and vaccination schedules. Pleuritis and cranio-ventral pulmonary consolidation lesions were recorded in 26.8% and 55.7% of slaughter-aged pigs, respectively. Among lungs with pleuritis, 50.1% had lesions compatible with Actinobacillus pleuropneumoniae (App) infection. Antibodies to porcine reproductive and respiratory syndrome (PRRSV), three subtypes (H1N1, H1N2 and H3N2) of swine influenza virus (SIV), App and Mycoplasma hyopneumoniae (Mhyo) were highly prevalent (>82%) in most of the farms. In a multivariable analysis, it was estimated (R(2)=0.40) that the percentage of animals with pleuritis compatible with App infection depended on the existence of an all in-all out by room management system and App and PRRSV herd seroprevalence. Moreover, it was possible to foresee (R(2)=0.59) that cranio-ventral pulmonary consolidation lesions (EP-like lesions) were affected by the type of farm ventilation, the presence of respiratory symptoms during the fattening period and Mhyo and SIV H1N2 herd seroprevalence.

Genetic algorithm modeling for the inspection allocation in reentrant production systems

One of the most important characteristics of reentrant production systems is that the products are manufactured layer-by-layer, so it is difficult to inspect some defects after they are covered by the next layer. This study proposes a genetic algorithm (GA) approach that is very suitable for solving the inspection allocation problem, because the codes used in the chromosome of the GA approach are exactly the same as the representation of the inspection allocation policy for workstations in the production system. Meanwhile, this study shows better performance than the researches done in the literature and is very much closer to the optimization method based on complete enumeration. In addition, a discussion regarding GA parameters is performed to suggest proper parameters used for various production systems. The result obtained in this study is highly practical, extensible and applicable, so it can serve as a production planning tool to solve the inspection allocation problem in reentrant production systems.

Web hypermedia content management system effort estimation model

This study aims at creation of a well defined estimation model which can be used to estimate the effort required for designing and developing the web hypermedia content management systems. The data from the different content management system projects are studied and the linear regression approach is used to finalize the model. This model also provides guidelines to calculate phase wise distribution of effort. The model is designed to help project manager to estimate effort at the very early stage of requirement analysis. A set of questionnaire is used to estimate the complexity of the project, which has to be filled after completing the initial requirement analysis. Final effort is estimated using the project size and the different adjustment factors. For better calculation of these adjustments factors, these are categorized into three categories based on their characteristics such as Production and General system characteristics. This model is proposed to be used differently for the different types of projects. These projects are categorized based on their size and total/build effort ratio. The size of the project is estimated by using the modified object point analysis approach. The estimated effort is further phase wise distributed for better scheduling of the project. Another questionnaire is used to refine the model and it has to be filled by the project managers after completing the project. The proposed model is validated by studying twelve completed projects taken from industry and seventy different projects completed by the students. The proposed model shows a great improvement as compared to the earlier models used in effort estimation of CMS projects.

Production system selection for the agile manufacturing of modularly designed products

This paper provides insight into a selection method for production systems from amongst competing alternatives having varying degrees of tangible and intangible advantages and benefits. The specific production system characteristics investigated in this study are for discrete and modularly designed products: products that are designed in such a way that they can be manufactured in modules and thus support the strategy of mass customisation. These products and characteristics are core dimensions and aspects for successful agile manufacturing environment implementations. The decision environment is limited to in-family variations in the products. The Analytical Network Process (ANP) is the methodological approach applied for the production system selection.

Value‐based labels for fresh beef: an overview of French consumer behaviour in a BSE crises context

AbstractIn the last decade, the French beef industry has been through two major health scares related to bovine spongiform encephalopathy. This paper describes and discusses changes in beef supply in France from the consumer's perspective. The authors review the initiatives implemented in each crisis and show that the immediate effects (slump in consumption), however spectacular, were not the most lasting effects. By contrast, responses from the industry and the authorities brought about a far‐reaching change in practices by requiring new instruments to be used (traceability). Yet the information conveyed by this innovation cannot readily be appropriated by consumers who are not conversant with the characteristics of beef production systems.

Les produits d’origine entre cultures et règlements

Localized agri-food products stand at the crossroads of multiple converging interests that attract an ever-wider audience. The regulations protecting origin-based products raise complex questions regarding notions of tradition, place, origin, reputation or customs. Plainly however, the survival of such products depends on appropriate standards particularly in terms of sanitary requirements - that reflect the specific characteristics of local production systems and small-scale manufacturing units.

Tipologia de sistemas de produção bovina com ênfase na ocorrência de ectoparasitoses

Este estudo foi realizado para identificar, por meio da utilização de procedimentos de pesquisa diagnóstica, características dos sistemas de produção relacionadas à ocorrência de ectoparasitos. Foram aplicadas entrevistas semi-estruturadas em 62 propriedades, cujos dados foram analisados por procedimentos estatísticos multivariados. Observou-se maior importância da área das propriedades, do manejo de pastagens e da freqüência de visitas do proprietário ao seu estabelecimento. O método utilizado, a época e a freqüência das aplicações de carrapaticidas destacaram-se entre as medidas de controle de ectoparasitoses. Os resultados reafirmaram a importância dos procedimentos de pesquisa diagnóstica como ferramenta de identificação de problemas técnicos e econômicos de sistemas de produção e de representação de sua diversidade, subsídios indispensáveis para o desenvolvimento de trabalhos experimentais mais coerentes com a realidade produtiva do estado.

A REVIEW OF URBAN AND PERI-URBAN VEGETABLE PRODUCTION IN WEST AFRICA

ISHS XXVII International Horticultural Congress - IHC2006: International Symposium on Horticultural Plants in Urban and Peri-Urban Life A REVIEW OF URBAN AND PERI-URBAN VEGETABLE PRODUCTION IN WEST AFRICA

Dynamic scheduling of production-assembly networks in a distributed environment

In complex manufacturing environments, meeting the due dates of the jobs and minimizing in process inventories are important performance metrics. One of the common characteristics of complex production systems is production-assembly network of operations. This paper presents an auction-based algorithm for simultaneous scheduling of all manufactured and assembled jobs in a dynamic environment, where the objective function is to minimize both the due date penalties associated with the final products and the inventory cost of the work in process. An auction-based approach using a Mixed-Integer Linear Programming (MILP) model to construct and evaluate the bids so that the auction mechanism mimics a Lagrangian relaxation-based subgradient optimization to ensure global optimality is proposed. The inner structure of the problem enables very efficient calculation of bids for each job or assembly. Using a full factorial experimental design the properties of the proposed algorithm are analyzed. Results show that the proposed auction based algorithm performs better than the popular dispatching rules and is more scalable than the MILP model or direct implementations of the subgradient algorithm. Furthermore, the proposed algorithm is designed to work in a dynamic environment.

SMALL-SCALE DAIRY FARMING IN THE HIGHLANDS OF CENTRAL MEXICO: TECHNICAL, ECONOMIC AND SOCIAL ASPECTS AND THEIR IMPACT ON POVERTY

Small-scale dairy farming has been suggested as a rural development option for Mexican campesino communities. However, there is a lack of information on how dairy farming systems operate. The objective of this paper is to analyse the social, productive and economic characteristics of small-scale dairy production systems in the central highlands in the northwest of the State of Mexico. These three characteristics were analysed on 69 farms using factor and cluster analysis. Five factors accounted for 68% of cumulative variance. Cluster analysis yielded three well-defined groups. A Kruskal–Wallis test was performed on the arable land area and the number of animals, and analysis of variance for milk yield. Economic analysis was undertaken using activity budgets. Results showed the relationships between scale and management methods and their effects on the income for the family. Families in only one of the three groups receive incomes from dairying that were above all Mexican poverty indices. This outcome is explained by the intensification in the management of their herds, which is reflected in higher milk yields, higher incomes and better access to government support schemes. Enhancement of milk production in the area studied needs differential policies which take in to account differences between the groups identified.

Layer modelling for the inspection allocation problem in re-entrant production systems

In the past two decades, re-entrant production systems have received a great deal of attention. One of the most important characteristics of re-entrant production systems is that the work units are manufactured layer-by-layer, so that some defects are more difficult to inspect after they are covered by the next layer. In this research, a mathematical model considering layered fabrication is developed to find the optimal solution for allocating inspections in re-entrant production systems. Workstations of variables data and inspections of quality characteristics measurement are modelled. In addition, this study considers three possibilities for the treatment of detected non-conforming units, namely repair, rework and scrap. Moreover, a heuristic algorithm is proposed in order to improve the optimization method based on complete enumeration, which suffers from a large amount of computation time, especially as the number of workstations increases. The model is highly extensible and applicable, so it can serve as a production-planning tool to solve the inspection allocation problem in re-entrant production systems.

A Cue for Objective Speech Quality Estimation in Temporal Envelope Representations

In this paper, we investigate a new paradigm of objective speech quality estimation. The proposed nonintrusive method utilizes only processed speech signal, whereas conventional objective models require source speech applied as an input to the system under test, as well as the processed speech. The proposed method is based on the temporal envelope representation of speech, which reflects the perceptual characteristics of human auditory systems and human speech production systems, and we found it provides a useful cue for nonintrusive objective speech quality estimation. The performance of the proposed method is demonstrated for four different subjective mean opinion score databases.

Is benthic trophic structure affected by food quality? The Dogger Bank example

The aim of this study was to evaluate the relationship between food quality and trophic structure of macrobenthic communities of the Dogger Bank. Therefore, 21 stations along different depth gradients (a transect across the central Dogger Bank and at a station ‘cross’ in the north-eastern part) were sampled and analysed for macrofauna trophic structure and food supply, indicated by phytopigment composition and organic matter contents of the sediment. The study revealed differences in the trophic structure of the benthic community in areas with contrasting food supply. The trophic structure reflected differences in relative quality of organic matter. The sandy sediments on top of the bank receiving intermediate quantities of high food quality were inhabited by high abundances of interface feeders and sand-licking amphipods of the genus Bathyporeia. The southern stations characterised by a comparatively high amount of intermediate food quality were dominated by interface feeders such as Amphiura filiformis. The northern and north-eastern stations showing the highest diversity of feeding types were characterised by a comparatively low, but highly variable input of intermediate-quality organic matter consisting of both fresh and degraded organic matter. Results are discussed with a special emphasis on specific Dogger Bank features such as benthic primary production and frontal system characteristics.

Selection of knowledge acquisition techniques based upon the problem domain characteristics of production and operations management expert systems

The application of expert systems to various problem domains in business has grown steadily since their introduction. Regardless of the chosen method of development, the most commonly cited problems in developing these systems are the unavailability of both the experts and knowledge engineers and difficulties with the process of acquiring knowledge from domain experts. Within the field of artificial intelligence, this has been called the ‘knowledge acquisition’ problem and has been identified as the greatest bottleneck in the expert system development process. Simply stated, the problem is how to acquire the specific knowledge for a well‐defined problem domain efficiently from one or more experts and represent it in the appropriate computer format. Given the ‘paradox of expertise’, the experts have often proceduralized their knowledge to the point that they have difficulty in explaining exactly what they know and how they know it. However, empirical research in the field of expert systems reveals that certain knowledge acquisition techniques are significantly more efficient than others in helping to extract certain types of knowledge within specific problem domains. In this paper we present a mapping between these empirical studies and a generic taxonomy of expert system problem domains. In so doing, certain knowledge acquisition techniques can be prescribed based on the problem domain characteristics. With the production and operations management (P/OM) field as the pilot area for the current study, we first examine the range of problem domains and suggest a mapping of P/OM tasks to a generic taxonomy of problem domains. We then describe the most prominent knowledge acquisition techniques. Based on the examination of the existing empirical knowledge acquisition research, we present how the empirical work can be used to provide guidance to developers of expert systems in the field of P/OM.

A theory of speech motor control and supporting data from speakers with normal hearing and with profound hearing loss

A theory of the segmental component of speech motor control is presented, followed by supporting data. According to the theory, speech movements are programmed to achieve auditory/acoustic goals. The goals are determined partly by “saturation effects”, which are basic characteristics of speakers' production systems that make it possible to produce a sound output that has some relatively stable acoustic properties despite a somewhat variable motor input. The programming of articulatory movements to achieve auditory goals utilizes an internal model (or “mapping”) of relations between articulatory configurations and their acoustic consequences. The internal model is acquired and maintained with the use of auditory feedback. The supporting data for this theory come from experiments on speakers with normal hearing, cochlear implant users and a patient with neurofibromatosis-2.

Definition of animal breeding goals for sustainable production systems.

What we do is determined by the way we "view" a complex issue and what sample of issues or events we choose to deal with. In this paper, a model based on a communal, cultural, or people-centered worldview, informed by a subjective epistemology and a holistic ontology, is considered. Definitions and interpretations of sustainable agriculture are reviewed. Common elements in published definitions of sustainable agriculture and animal production among those who seek long-term and equitable solutions for food production are resource efficiency, profitability, productivity, environmental soundness, biodiversity, social viability, and ethical aspects. Possible characteristics of future sustainable production systems and further development are presented. The impact of these characteristics on animal breeding goals is reviewed. The need for long-term biologically, ecologically, and sociologically sound breeding goals is emphasized, because animal breeding determined only by short-term market forces leads to unwanted side effects. Hence, a procedure for defining animal breeding goals with ethical priorities and weighing of market and non-market values is suggested. Implementation of non-market as well as market economic trait values in the aggregate genotype, as suggested, may allow for breeding programs that contribute to sustainable production systems. Examples of breeding goals in salmon, cattle, and pigs are given, and the resulting genetic responses are evaluated with respect to economic profit (or costs) and other criteria of sustainability. Important prerequisites for breeding programs for sustainable production are appropriate governmental policies, awareness of our way of thinking, and a more communal worldview informed by a subjective epistemology and a holistic ontology.

General structure and characteristics of quick response production system

The diversification and shorter production cycles urge manufacturers to shift their production systems from “make to stock” to “make to order” or an intermediate production system between them. The present paper deals with a production system developed by some manufacturers to meet requirements in the last decade. The system, which we call “Quick response to orders production system” or in brief “quick response production system (QRPS)”, is characterized by two key factors, i.e., “acceptable response time” and “semifinished product.” An acceptable response time is decided through the explicit or implicit approval of customers beforehand and manufacturers guarantee to ship products within an acceptable response time in a stochastic sense by processing the semifinished product according to customer order. As a result, manufacturers are able to reduce the inventory of finished products, while customers are able to enjoy the diversification of products and a stable supply from manufacturers. The general structure and characteristics of QRPS are discussed primarily from a quantitative point of view and a numerical example is shown to assist in understanding the design and operation of QRPS.

Configuration and coordination of virtual production networks

Following the actual discussion concerning modern production concepts, the term “virtual production” or “virtual enterprise” plays an increasingly important role. The idea of virtual enterprises is to implement modern management trends like “concentration on core competencies”, “distributed production” and “maximal customer orientation” by the application of advanced computer and telecommunication systems and services like “global networking” or “groupware systems”. The objective is to establish a certain kind of a “Best of everything Organization” by a synergetic combination of core competencies of single partners (centers of competence) in order to perform a given business project to a maximum degree of customer satisfaction. Important features are a distinct form of network organization in combination with a high degree of organizational flexibility. Taking into account Williamson's theory of transactions costs, virtual enterprises can be interpreted as a certain kind of an intermediate organizational form between the institutional poles: market and hierarchical structured enterprises. According to this an evaluation will be given on the basis of transaction costs. In the following section structural and process-orientated questions of virtual production systems are formulated. From the viewpoint of production science, especially the allocation of sub-tasks to adequate project partners and the harmonization of distributed production processes in a network of independent companies seems to be very interesting. Principally, the decision support systems for such problems can be based on hierarchical or distributed control strategies. The characteristics of virtual production systems imply the application of decentralized approaches (e.g. multi-agent systems). A very interesting approach in this context is the application of distributed problem-solving strategies like contract networks.

Local innovative capability and innovative adoption in agriculture: Computers on Italian farms

The paper examines the role of the local environment in determining farmers' innovative behavior. The local environment embodies an innovative capability that helps farms to bridge the knowledge gap associated with innovation adoption. This capability is generated by the formal and informal relationships established by the economic units and institutions within the local environment, which allow the creation and circulation of new knowledge and skills. Local innovative capability is defined through composite variables identified by applying principal component analysis to a set of variables measuring characteristics of local society, production systems and agriculture. The model was tested by analysing computer ownership by Italian farms at provincial level. Empirical analysis confirms the importance of the local innovative capability for farmers' innovative behaviour. The propensity to innovate is further enhanced if farm structures are well endowed. Copyright 1998 by Oxford University Press.

Economic and Environmental Simulation of Alternative Cropping Sequences in Michigan

When designing and implementing alternative cropping sequences for on-farm testing, researchers may ignore economic feasibility as a criterion for selecting among technologically feasible alternatives. We develop a theoretically consistent approach for simulating economic returns and environmental characteristics of field level production systems that may be used for ex ante evaluation. The SMART-FRMS system is used to simulate the environmental characteristics and a net present value model is used for economic comparisons between systems for a farm in Michigan. Two innovations in our method are the inclusion of transition period costs and annualization of returns for comparison of crop rotations of uneven lengths.