• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 162
  • 48
  • 11
  • 6
  • 4
  • 4
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 267
  • 267
  • 118
  • 109
  • 42
  • 28
  • 26
  • 24
  • 23
  • 23
  • 20
  • 19
  • 18
  • 18
  • 18
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Towards a Holistic Development Approach for Adaptable Manufacturing Paradigms : A Case Study of Evolvable Production Systems

Rahatulain, Afifa January 2016 (has links)
Increasing global competition, market uncertainties and high product variance are a few of the factors posing challenges to the existing manufacturing industry. Having a quick response to market fluctuations and adapting to changing customer demands while maintaining shorter lead times and low costs are a few of the major challenges. The main focus of this thesis is on Evolvable Production Systems, which is one of the promising solutions to deal with the emerging manufacturing challenges by changing the conventional manufacturing systems towards a more flexible, intelligent and adaptable approach. Although promising, further research is needed in several directions for a wider industrial acceptance of EPS. The directions include but are not limited to methodological aspects, tool support, etc. throughout the development lifecycle. This thesis aims to provide a basis for a holistic model-based development methodology for evolvable production systems. One of the main contributionsof this work is the identification of major architectural elements (i.e stakeholders,concerns, viewpoints and views) and their dependencies on each other.This work shall serve as a basis for establishing a well-defined architectural framework for EPS. The second important contribution of this thesis is the development of a domain specific modeling language (EPS- DSL) based on the existing EPS ontology. The DSM platform does not only store the domain knowledge in the form of models but also provides support for the re-use of these models, i.e. enables utilization of the domain ontology during system development. Moreover, the automatic code generation support for the module library presented in this work, significantly reduces the risks of information discrepancies when transferring data from one abstraction level to another. The existing EPS ontology is also evaluated from a holistic perspective and resulted in contributing a few improvement suggestions for achieving a seamless model-based development approach. Evaluation of Simulink/SimEvents as a modeling and simulation tool for EPS is the third main contribution of this thesis. One of the main advantages of evaluating this tool for EPS is the opportunity to analyze the complete system behavior on a single modeling platform. The integration of agent-based system behavior (discrete event) with dynamic system behavior (continuous &amp; discrete time) provides a holistic modeling approach and implies less information inconsistencies. / <p>QC 20160429</p>
82

Sustainable Production Systems: Drivers and Measurement for the Swedish Start-Up Food and Beverage Industry

Akay, Serdar January 2022 (has links)
Sustainability is one of the main concerns for businesses in order to being competitive in the market. Sustainability is one the most important and popular fields for the companies due to customer expectations and profitability. Therefore, there is a need to comprehend sustainability in production systems in order to encounter drivers, transform production systems with smart tools, and evaluate the measurements in production systems. The purpose of this thesis is to investigate how to achieve sustainability goals for start-up companies and how these companies can incorporate sustainability in order to improve their production systems. Literature study was performed to build a theoretical foundation for this thesis, therefore allowing the opportunity to answer the research questions of this thesis. The literature study was covered to identified aspects, including drivers of sustainable production systems, sustainability indicators, and technological developments in the production systems. To answer the research questions a single case study was carried out. The company was a start-up company in the food and beverage industry. Data was collected through questionnaires, document review, interviews, and observations. An investigation regarding sustainability goals and measurement indicators are critical when implementing sustainability practices in the production systems. The outcome from these investigations set a knowledge for improving production systems to better meet sustainability goals. To measure sustainability indicators, there is a need to correct data collection and understand how to use the equations. The measurement indicators identified in production systems having a direction to measure environmental aspects in the production systems. The technological improvements have an impact on the motivation regarding sustainability indicators in order to decrease energy consumption, waste and water management, emissions, and production efficiency, as well as decreasing the cost. This thesis provides a knowledge for the start-up company in order to implement sustainability aspects in the production systems to better meet sustainability goals. Additionally, highlights areas of drivers factor and measurement indicators for integration of sustainability in the production systems.
83

An exploratory investigation of the implementation of Lean in a UK automotive plant

McSweeney, Andrew S. January 2017 (has links)
This thesis reflects upon several decades of research into Lean Production systems, highlighting the need for further investigation using an empirical study of exemplar implementations of Lean. The initial point of departure is an analysis of the current views of Lean based on a detailed literature review. The resulting Views of Lean Table provides a framework for the investigation of an exemplar Lean operation, viz the Nissan Sunderland Plant, widely regarded to be one of the most productive automotive plants in Europe. The exploratory nature of this investigation, and unique opportunity for access, argued for the use of an inductive single case study as an appropriate research approach. A four phase approach was used to; a) identify views of Lean, b) gain an initial understanding of the Nissan Production Way at the Nissan Sunderland Plant, b) acquire a detailed description of the Nissan Production Way and c) to assess the level of intrinsic motivation amongst employees. The primary objective of this research is to establish whether our current knowledge of Lean sufficiently encapsulates the concept’s many facets. Detailed semi-structured interviews with Nissan Production Way experts revealed that Nissan Sunderland Plant’s production system uses a large number of elements in contrast to the relatively narrow list of ‘Lean’ elements cited in the Views of Lean Table. In contrast to academic theory there was a focus on extrinsic motivation with low intrinsic motivation offset by the plant’s continuous fight for survival and ‘whatever-it-takes’ attitude. In practice Lean is viewed as an overarching philosophy with a toolkit encompassing a wide range of tools which are used when they are suitable for the task in hand.
84

Adaptive manufacturing: dynamic resource allocation using multi-agent reinforcement learning

Heik, David, Bahrpeyma, Fouad, Reichelt, Dirk 13 February 2024 (has links)
The global value creation networks have experienced increased volatility and dynamic behavior in recent years, resulting in an acceleration of a trend already evident in the shortening of product and technology cycles. In addition, the manufacturing industry is demonstrating a trend of allowing customers to make specific adjustments to their products at the time of ordering. Not only do these changes require a high level of flexibility and adaptability from the cyber-physical systems, but also from the employees and the supervisory production planning. As a result, the development of control and monitoring mechanisms becomes more complex. It is also necessary to adjust the production process dynamically if there are unforeseen events (disrupted supply chains, machine breakdowns, or absences of staff) in order to make the most effective and efficient use of the available production resources. In recent years, reinforcement learning (RL) research has gained increasing popularity in strategic planning as a result of its ability to handle uncertainty in dynamic environments in real time. RL has been extended to include multiple agents cooperating on complex tasks as a solution to complex problems. Despite its potential, the real-world application of multi-agent reinforcement learning (MARL) to manufacturing problems, such as flexible job-shop scheduling, has been less frequently approached. The main reason for this is most of the applications in this field are frequently subject to specific requirements as well as confidentiality obligations. Due to this, it is difficult for the research community to obtain access to them, which presents substantial challenges for the implementation of these tools. ...
85

Model-Based Trust Assessment in Autonomous Cyber-Physical Production Systems

Zahid, Maryam January 2024 (has links)
An increase in consumer demand and scarcity of available resources has led industrialists to hunt for solutions related to the automation of traditional manufacturing and production processes, optimizing resource consumption while improving the overall efficiency of the process. The resultant revolution brought forward the concept of cyber-physical production systems. Furthermore, industries within the private sector have integrated artificial intelligence with their traditional production processes as Cobots (collaborative robots), thus introducing the concept of Autonomous Cyber-Physical Production Systems. Although these systems maximize the production or manufacturing process while efficiently using the available resources, the machine learning component integrated into the traditional cyber-physical production system brings about trust-related issues due to its possible lack of predictability and transparency. Implementing trust-related attributes within autonomous cyber-physical production systems alone cannot overcome the highlighted problem. Therefore, a detailed risk assessment is required to identify and assess any trust-related risks in the system, especially at the early stages of the software development life cycle, to avoid major incidents and reduce maintenance costs. Based on the above-stated facts, this research proposes a model-based risk assessment technique for evaluating the trustworthiness of autonomous cyber-physical production systems. The proposed technique focuses on the identification and assessment of trust-related risks originating from the dynamic behavior of the machine learning component in autonomous cyber-physical production systems. For this, we use existing standards and techniques proposed for risk assessment in cyber-physical production systems as common ground to facilitate better implementation of trustworthiness in autonomous cyber-physical production systems. The proposed technique is aimed at overcoming the structural and behavioral limitations reported in existing model-based risk assessment techniques when dealing with autonomous cyber-physical production systems.
86

Quality Control Tools for Cyber-Physical Security of Production Systems

Elhabashy, Ahmed Essam 15 January 2019 (has links)
With recent advancements in computer and network technologies, cyber-physical systems have become more susceptible to cyber-attacks; and production systems are no exception. Unlike traditional Information Technology (IT) systems, cyber-physical systems are not limited to attacks aimed at Intellectual Property (IP) theft, but also include attacks that maliciously affect the physical world. In manufacturing, such cyber-physical attacks can destroy equipment, force dimensional product changes, alter a product's mechanical characteristics, or endanger human lives. The manufacturing industry often relies on modern Quality Control (QC) tools to protect against quality losses, such as those that can occur from an attack. However, cyber-physical attacks can still be designed to avoid detection by traditional QC methods, which suggests a strong need for new and more robust QC tools. Such new tools should be able to prevent, or at least minimize, the effects of cyber-physical attacks on production systems. Unfortunately, little to no research has been done on using QC tools for cyber-physical security of production systems. Hence, the overarching goal of this work is to allow QC systems to be designed and used effectively as a second line of defense, when traditional cyber-security techniques fail and the production system is already breached. To this end, this work focuses on: 1) understanding the role of QC systems in cyber-physical attacks within manufacturing through developing a taxonomy encompassing the different layers involved; 2) identifying existing weaknesses in QC tools and exploring the effects of exploiting them by cyber-physical attacks; and 3) proposing more effective QC tools that can overcome existing weaknesses by introducing randomness to the tools, for better security against cyber-physical attacks in manufacturing. / Ph. D. / The recent technological developments in computers and networking have made systems, such as production systems, more vulnerable to attacks having both cyber and physical components; i.e., to cyber-physical attacks. In manufacturing, such attacks are not only capable of stealing valuable information, but can also destroy equipment, force physical product changes, alter product’s mechanical characteristics, or endanger human lives. Typically, the manufacturing industry have relied on various Quality Control (QC) tools, such as product inspection, to detect the effects caused by these attacks. However, these attacks could be still designed in a way to avoid detection by traditional QC methods, which suggests a need for new and more effective QC tools. Such new tools should be able to prevent, or at least minimize, the effects of these attacks in manufacturing. Unfortunately, almost no research has been done on using QC tools for securing production systems against these malicious attacks. Hence, the overarching goal of this work is to allow QC systems to be designed in a more effective manner to act as a second line of defense, when traditional cyber-security measures and attackers have already accessed the production system. To this end, this work focuses on: 1) understanding the role of QC systems during the attack; 2) identifying existing weaknesses in QC tools and determining the effects of exploiting them by the attack; and 3) proposing more effective QC tools, for better protection against these types of cyber-physical attacks in manufacturing.
87

An evaluation of different extensive wildlife production systems in the Western Cape Province of South Africa

Van Hoving, Susanna Catharina Petronella 03 1900 (has links)
Thesis (MScAgric (Agricultural Economics))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The wildlife industry in the Western Cape Province is growing, but lacks, particularly, economic research. This study explores the manner in which wildlife production systems in the Western Cape are currently operated and describes the characteristics of this industry. Furthermore, results on the evaluation of identified typical wildlife production systems in different regions of the Western Cape are revealed together with critical factors influencing success. No confusion remains regarding the importance of this industry. Wildlife production units cover a noteworthy percentage of the total area and are evenly spread within the province. The industry grew rapidly in the past 10 years and with a high diversity of at least 37 different wildlife species; ecotourism, hunting and live sales are the most prominent ways of utilising wildlife. This industry also contributes in terms of job opportunities supplied. The two typical systems evaluated are the biltong hunting system in the Beaufort West region and the trophy hunting system in the Southern Cape region. The biltong hunting system has been shown to be profitable, though it realises skimpy profits. It is, however, successful by virtue of the fact that wildlife producers perceive the wildlife enterprise as additional income to livestock production, almost without any additional costs. Although the gross margin per large stock unit is high, the trophy hunting system is not profitable and runs at a loss. The main problem is the overhead costs that exceed the gross margin, due to too low a number of wildlife species marketed. The industry in this region is, according to wildlife producers, hampered by legislation and regulations, which limit the variety of species allowed in the region. These wildlife producers manage their system on a part-time basis and fund it from other income sources. The Department of Agriculture is urged to assist the wildlife industry in the form of research on the economic, ecological and social impacts of this industry to determine its full contribution and capacity. Although wildlife producers contribute towards conservation and the application of sound conservation principles is important to them, they need to generate an income from wildlife production in order to make a living out of it, which ultimately makes it worth their while. Despite the systemic problems of a number of wildlife production systems, some wildlife producers are of the opinion that the pressure experienced in terms of legislation, makes it harder for them (in some regions more than other) to manage their wildlife production units in a profitable manner. Although the main objectives of government conservation authorities and wildlife producers might differ, the contribution of both towards conservation serves as common ground. It is therefore suggested that a joint approach is followed between government conservation authorities, the Department of Agriculture and wildlife producers to further develop the wildlife industry. / AFRIKAANSE OPSOMMING: Die wildbedryf in die Wes-Kaap groei tans, maar het ‘n tekort aan, veral, ekonomiese navorsing. Hierdie studie ondersoek die manier waarop wildproduksiestelsels tans in die Wes-Kaap Provinsie bedryf word en beskryf die karaktereienskappe van hierdie bedryf. Verder word die resultate van die evaluasie van die geïdentifiseerde tipiese wildproduksiestelsels in verskillende areas van die Wes-Kaap Provinsie bekend gemaak, tesame met die kritiese faktore wat sukses beïnvloed. Daar is geen twyfel oor die belangrikheid van hierdie bedryf nie. Wildplase beslaan ‘n betekenisvolle persentasie van die totale oppervlakte en is eweredig versprei in die provinsie. Die bedryf het vinnig gegroei in die laaste tien jaar en met ‘n groot verskeidenheid van minstens 37 verskillende wildspesies, is eko-toerisme, jag en lewende verkope die mees algemene manier om wild aan te wend. Die bedryf dra ook baie by in terme van werksgeleenthede. Die twee tipiese wildproduksiestelsels wat geëvalueer is, is die tipiese biltongjagstelsel in die Beaufort-Wes omgewing en die tipiese trofeejagstelsel in die Suid-Kaap omgewing. Die biltongjagstelsel toon winsgewend te wees, al is dit karige winste wat realiseer. Dit is egter suksesvol in die sin dat wildboere die wildvertakking sien as ‘n addisionele inkomste tot die lewendehawe produksie, amper sonder enige addisionele kostes. Alhoewel die bruto marge per grootvee-eenheid goed lyk, is die trofeejagstelsel nie winsgewend nie en maak ‘n verlies. Die eintlike probleem is die oorhoofse koste wat meer is as die bruto marge, as gevolg van te min en te klein verskeidenheid wild wat bemark word. Die bedryf in hierdie omgewing, na die mening van wildboere, word terug gehou deur wetgewing en maatreëls, wat die verskeidenheid wildspesies wat toegelaat word in die omgewing beperk. Hierdie wildboere bestuur hul stelsels op ‘n deeltydse basis en befonds dit vanuit ander inkomste bronne. Die Departement van Landbou word aangeraai om die wildbedryf by te staan in die vorm van navorsing op die ekonomiese, ekologiese en sosiale vlakke van die wildbedryf om sodoende die volle bydrae en omvang van hierdie bedryf te bepaal. Alhoewel wildboere bydra tot bewaring en die toepassing van suiwer bewaringsbeginsels vir hulle belangrik is, het hulle nodig om ‘n inkomste te genereer uit wildproduksie om sodoende ‘n bestaan daaruit te kan maak. Buiten die sistemiese probleme wat ondervind word by sommige wildproduksiestelsels, is party wildboere van mening dat die druk wat ervaar word in terme van wetgewing en maatreëls, dit vir hulle moeiliker maak om hul wildplase op ‘n winsgewende manier te bestuur. Alhoewel die doelwitte van die natuurbewaringsgesag en wildboere van mekaar mag verskil, dien die bydrae tot bewaring deur albei partye as gemeenskaplike grond. Om daardie rede word dit aanbeveel dat ‘n gesamentlike benadering tussen die regering se natuurbewaringsgesag, die Departement van Landbou en die wildboere gevolg word, om die wildbedryf verder te ontwikkel.
88

The effect of agricultural production system on the meat quality of Dorper lambs

Claasen, Claasen 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The aim of this study was to investigate the effect of South African production system (feedlot {FL-} or free-range {FR-}) and gender (ewes, rams or castrates) on growth and carcass characteristics of Dorper sheep. Male lambs (castrates and rams) grew twice as fast as ewes (P<0.05) under FL-conditions while much smaller differences were observed between gender groups in FR-lambs. FL-lambs produced heavier carcasses (P=0.0003) with higher dressing percentages (P<0.05) and greater carcass fatness levels (P<0.052) than FR- lambs. No differences attributable to production system were found on meat tenderness (as indicated by Warner Bratzler shear force strength) and on the intramuscular lipid concentration. In contrast, sensory evaluation results suggested that meat from FL-lambs was juicier and more tender than meat from FR-lambs. The sensory panel could not distinguish between FL and FR meat as far as the attributes of aroma and flavour were concerned. Cholesterol results indicated that for intermuscular fat, higher cholesterol levels were observed for FL-lambs than for FR-lambs. The level of palmitic acid (C16:0) was significantly higher (P=0.0375) in the Longissimus dorsi (LD) muscles of FL-lambs. For intramuscular fat from the Biceps femoris (BF) muscle, g-linolenic acid (C18:3n-6) was higher (P<0.0001) in FL- lambs. Results for intramuscular BF further indicated that ram lambs had the highest (P=0.0019) palmitic acid (C16:0) and sum of TUFA (P=0.0014), castrates had the highest (P=0.0260) α-linolenic acid (C18:3n-3) and g-linolenic acid (C18:3n-6), while ewe lambs had the highest (P=0.0014) SFA concentrations. Linoleic acid (C18:2n-6c) was significantly higher (P=0.0067) in the subcutaneous fat of FL-lambs while FR-lambs had more linolenic acid (C18:3n-3). For the kidney fat, FR-feeding increased (P < 0.05) stearic (C18:0), linolelaidic (C18:2n-6t), α-linolenic (C18:3n-3) and homo-g-linolenic acid (C20:3n-6) percentages. Conversely, linoleic acid (C18:2n-6c) was increased (P=0.0372) by FL-feeding. For the intermuscular fat, FR-lambs had higher linolenic acid (C18:3n-3) and SFA (P=0.0113 and P=0.0341) compared to FL-lambs. On the other hand, the sum of TUFA for the intermuscular fat was higher (P=0.0341) in FL-lambs compared to FR-lambs. Results from the study imply that the consumer may not necessarily be able to discern between meat from FR- or FL-lambs, although they may possibly discriminate against the increase in visible fatness of FL-lambs. No clear advantage of production system in terms of human health could be demonstrated as far as the proximate chemical composition and the fatty acid composition of the meat was concerned. The faster growth and the associated shorter production cycle of FL-lambs could be an advantage under certain production systems. However, it needs to be weighed against the cost of concentrate feeding and the preference consumers are likely to develop for lamb produced in natural environments. / AFRIKAANSE OPSOMMING: Die doel van die studie was om Suid Afrikaanse produksiestelsel (voerkraal {VK-} of veld {VD}) en geslag (ooie, hamels of ramme) op die groeivermoë en karkaseienskappe van die Dorperskape te bepaal. Manlike lammers (ramme and hamels) het twee keer vinniger (P<0.05) as ooilammers onder VK-toestande gegroei, terwyl kleiner verskille tussen geslagsgroepe by VD-diere waargeneem is. VK-lammers het swaarder karkasse (P=0.0003), hoër uitslagpersentasies (P<0.05) en meer karkas vet (P<0.052) as VD -lammers vertoon. Geen verskille as gevolg van produksiestelsel is op die sagtheid van vleis (soos aangedui deur Warner-Bratzler skeurkragwaardes) en die binnespierse vetinhoud gevind nie. Daarenteen het sensoriese analises aangedui dat vleis van VK-lammers sappiger en sagter as vleis van VD- lammers was. Die sensoriese paneel kon nie verskille aangaande die aroma en geur van vleis tussen VK- en VD-vleis onderskei nie. Cholesterolvlakke was hoër vir VK-lammers as by VD-lammers. Die vlak van palmitiese suur (C16:0) was hoër (P=0.0375) in die Longissimus dorsi (LD) spier van VK-lammers. Vir binnespierse vet van die Biceps femoris (BF) spier was g-linoleniese suur (C18:3n-6) hoër (P<0.0001) in VK-lammers. Resultate vir binnespierse vet van die BF spier het verder bewys dat ramlammers die hoogste (P=0.0019) palmitiese suur (C16:0) and totale onversadigde vetsure (P = 0.0014) getoon het, hamels die hoogste (P=0.0260) α-linoleniese suur (C18:3n-3) en g-linolenese suur (C18:3n-6) getoon het terwyl ooilammers die hoogste (P=0.0014) versadigde vetsuurvlakke getoon het. Linoliese suur (C18:2n-6c) was hoër (P=0.0067) in die onderhuidse vet van VK-lammers terwyl VD-lammers meer linoliese suur (C18:3n-3) gehad het. Resultate vir niervet het getoon dat VD-voeding die persentasies van steariese (C18:0), linoleladiese (C18:2n-6t), α-linoleniese (C18:3n-3) and homo-g-linoleniese suur (C20:3n-6) verhoog (P<0.05) het relatief tot VK-voeding. Linoliese suur (C18:2n-6c) is deur VK-voeding verhoog (P=0.0372). Vir intermuskulêre vet het VD-lammers hoër linoleniese suur (C18:3n-3) en versadigde vetsure (P=0.0113 en P=0.0341) as VK-lammers gehad. Die totale onversadigde vetsure vir tussenspiere vet was hoër (P=0.0341) in VK-lammers in vergelyking met VD-lammers. Resultate van hierdie studie dui daarop dat verbruikers nie noodwendig tussen vleis van VD- en VK-lammers sal onderskei nie, alhoewel hulle dalk teen die sigbaar vetter vleis van VK-lammers kan diskrimineer. Geen definitiewe voordeel in terme van menslike gesondheid kon op grond van die chemiese samestelling van die vleis bevestig word nie. Vinniger groei van VK-lammers, en die korter produksiesiklus wat daarmee verband hou, mag onder sekere produksie stelsels ʼn voordeel wees. Die voordeel moet teen die hoër koste van VK-voeding en die voorkeur van verbruikers vir lam produksie in natuurlike omgewing opgeweeg word.
89

Nutritional, sensory, and quality attributes of heritage bred chicken and commercial broiler meat

Christiansen, Alexandra R. January 1900 (has links)
Master of Science / Department of Food Science / Elizabeth A. Boyle / Animal production factors can affect nutritional composition and quality of poultry meat. Quality attributes and fatty acid composition were evaluated on breast and thigh meat with skin from free range, heritage bred chickens (>116 day of age) (HB) and commercial broilers (<50 day of age) (CM). In addition, sensory and textural attributes were evaluated on breast and thigh meat of HB, and air or water chilled CM. Moisture and fat content was similar (P>0.05) between chicken types without skin. Thigh meat had at least 2.41% more fat (P<0.05) than breast meat; however, breast meat had at least 2.33% more moisture (P<0.05) regardless of skin inclusion or chicken type. Heritage meat with or without skin had a greater amount (P<0.05) of ω3 polyunsaturated fatty acids (PUFA) than CM regardless of chilling type and HB had a lower, more desirable ω6:ω3 ratio of 12.79 when compared to air or water chilled CM at 15.20 and 14.77, respectively. Heritage breast and thigh meat with skin contained 35.60 and 35.21% PUFA which was greater than (P<0.05) CM breast and thigh meat with skin at 20.96 and 20.45%, respectively. Whole carcass weight of CM, breast weight, and bone-in thigh weight was 71.30%, 148.0%, and 52.2% heavier (P<0.05), respectively, than HB weight. However, bone-in thigh yield was 2.1% higher (P<0.05) in HB. Commercial broiler breast and thigh meat was more tender (P<0.05) with higher myofibrillar tenderness and overall tenderness values and having less connective tissue than HB breast and thigh meat. Thigh meat from HB also had the highest (P<0.05) peak force values for Warner-Bratzler (3.47 kgf) and Allo-Kramer (7.22 kgf/g sample) shear tests. Thigh meat was perceived to be more juicy (P<0.05) and have more chicken flavor intensity (P<0.05) than breast meat. Heritage meat showed advantages in fatty acid profiles while CM meat showed advantages in yields and tenderness attributes.
90

Modelagem de sistemas de controle distribuídos e colaborativos de sistemas produtivos. / Modeling of distributed collaborative control systems of production systems.

Matsusaki, Cristina Toshie Motohashi 27 October 2004 (has links)
O rápido avanço tecnológico nestes últimos anos, principalmente dos recursos computacionais e de comunicação, permite que os sistemas produtivos (SP) evoluam tanto no seu aspecto estrutural quanto no comportamental para que atendam às necessidades crescentes do mercado. Os elementos integrantes dos SP vêm incorporando estes avanços, atingindo maior autonomia e flexibilidade p ara cumprir suas funcionalidades. Além disso, a tendência dos dispositivos de controle de incorporar a capacidade de atuação em ambientes distribuídos onde a interação ocorre através de redes de comunicação, verificada na evolução das normas aplicadas a sistemas de controle, reflete a necessidade de aderência dos sistemas de controle a essa realidade. A necessidade de se manter competitivo no mercado impõe aos atuais SP situações em que emergem novos desafios para realização do controle dos seus processos globais, uma vez que estes assumem múltiplos objetivos, envolvendo diferentes naturezas de indeterminismo, assincronismo e variância no tempo, provocando um nível de complexidade inédito no que se refere ao controle destes sistemas. Este trabalho propõe inicialmente uma nova abstração para modelar-se os SP baseada no conceito de decomposição multidimensional e em múltiplas faces, distribuindo o controle através dos componentes colaborativos. Feito isto, são propostos procedimentos e técnicas para modelagem de sistemas de controle distribuídos e colaborativos (SCDC) de SP. Considera-se para isso, primeiro, uma arquitetura lógica de controle que contemple os múltiplos domínios semânticos presentes em SP, que são provenientes das especificidades dos elementos integrantes. Segundo, a multiplicidade de habilidades necessárias para garantir a execução das estratégias de controle pertinentes a cada domínio. Terceiro, o fluxo de informações heterogêneas provenientes das interações colaborativas entre os domínios. / Recent technological advances, mainly of computer and communication systems, allow the production systems (SP) to evolve in structural aspect as well as in behavioral aspect. The SP resources have achieved enhanced autonomy and flexibility with embedded computer and communication capability. Latest trends of control devices, as seen in the evolution of standards related to control systems, focus on the use of these devices in a distributed environment, where interaction occur through a communication network Thus, the SP control system and its design methods have to fit to this reality. In a competitive scenario, the SP are challenged to keep control of the global processes, considering the multiple goals of these processes and the involvement of different aspect of indeterminism, lack of synchronisms and time variance, generating a inedited complexity level for control of this systems. This work proposes a new abstraction for modeling the control systems of SP, based on the concept of multidimensional decompositions. Based on this, it introduces the procedures and techniques for modeling the distributed and collaborative control systems (SCDC) of the production systems. First, it considers the logic architecture of the control that support many semantic domains presented in this type of SP. Then, the diversity of skills related to each domain necessary to accomplish the control strategies. And then, the heterogeneous information flow through the domains boundaries, derived from the collaborative interaction between the control components.

Page generated in 0.0212 seconds