Design and Management of Manufacturing Systems

Although the design and management of manufacturing systems have been explored in the literature for many years now, they still remain topical problems in the current scientific research. The changing market trends, globalization, the constant pressure to reduce production costs, and technical and technological progress make it necessary to search for new manufacturing methods and ways of organizing them, and to modify manufacturing system design paradigms. This book presents current research in different areas connected with the design and management of manufacturing systems and covers such subject areas as: methods supporting the design of manufacturing systems, methods of improving maintenance processes in companies, the design and improvement of manufacturing processes, the control of production processes in modern manufacturing systems production methods and techniques used in modern manufacturing systems and environmental aspects of production and their impact on the design and management of manufacturing systems. The wide range of research findings reported in this book confirms that the design of manufacturing systems is a complex problem and that the achievement of goals set for modern manufacturing systems requires interdisciplinary knowledge and the simultaneous design of the product, process and system, as well as the knowledge of modern manufacturing and organizational methods and techniques

Supervisory Control and Analysis of Partially-observed Discrete Event Systems

Nowadays, a variety of real-world systems fall into discrete event systems (DES). In practical scenarios, due to facts like limited sensor technique, sensor failure, unstable network and even the intrusion of malicious agents, it might occur that some events are unobservable, multiple events are indistinguishable in observations, and observations of some events are nondeterministic. By considering various practical scenarios, increasing attention in the DES community has been paid to partially-observed DES, which in this thesis refer broadly to those DES with partial and/or unreliable observations. In this thesis, we focus on two topics of partially-observed DES, namely, supervisory control and analysis. The first topic includes two research directions in terms of system models. One is the supervisory control of DES with both unobservable and uncontrollable events, focusing on the forbidden state problem; the other is the supervisory control of DES vulnerable to sensor-reading disguising attacks (SD-attacks), which is also interpreted as DES with nondeterministic observations, addressing both the forbidden state problem and the liveness-enforcing problem. Petri nets (PN) are used as a reference formalism in this topic. First, we study the forbidden state problem in the framework of PN with both unobservable and uncontrollable transitions, assuming that unobservable transitions are uncontrollable. For ordinary PN subject to an admissible Generalized Mutual Exclusion Constraint (GMEC), an optimal on-line control policy with polynomial complexity is proposed provided that a particular subnet, called observation subnet, satisfies certain conditions in structure. It is then discussed how to obtain an optimal on-line control policy for PN subject to an arbitrary GMEC. Next, we still consider the forbidden state problem but in PN vulnerable to SD-attacks. Assuming the control specification in terms of a GMEC, we propose three methods to derive on-line control policies. The first two lead to an optimal policy but are computationally inefficient for large-size systems, while the third method computes a policy with timely response even for large-size systems but at the expense of optimality. Finally, we investigate the liveness-enforcing problem still assuming that the system is vulnerable to SD-attacks. In this problem, the plant is modelled as a bounded PN, which allows us to off-line compute a supervisor starting from constructing the reachability graph of the PN. Then, based on repeatedly computing a more restrictive liveness-enforcing supervisor under no attack and constructing a basic supervisor, an off-line method that synthesizes a liveness-enforcing supervisor tolerant to an SD-attack is proposed. In the second topic, we care about the verification of properties related to system security. Two properties are considered, i.e., fault-predictability and event-based opacity. The former is a property in the literature, characterizing the situation that the occurrence of any fault in a system is predictable, while the latter is a newly proposed property in the thesis, which describes the fact that secret events of a system cannot be revealed to an external observer within their critical horizons. In the case of fault-predictability, DES are modeled by labeled PN. A necessary and sufficient condition for fault-predictability is derived by characterizing the structure of the Predictor Graph. Furthermore, two rules are proposed to reduce the size of a PN, which allow us to analyze the fault-predictability of the original net by verifying that of the reduced net. When studying event-based opacity, we use deterministic finite-state automata as the reference formalism. Considering different scenarios, we propose four notions, namely, K-observation event-opacity, infinite-observation event-opacity, event-opacity and combinational event-opacity. Moreover, verifiers are proposed to analyze these properties

Environmental Impact Assessment by Green Processes

Primary energy consumption around the world has been increasing steadily since the Industrial Revolution and shows no signals of slowing down in the coming years. This trend is accompanied by the increasing pollutant concentration on the Earth’s biosystems and the general concerns over the health and environmental impacts that will ensue. Air quality, water purity, atmospheric CO2 concentration, etc., are some examples of environmental parameters that are degrading due to human activities. These ecosystems can be safeguarded without renouncing industrial development, urban and economic development through the use of low environmental impact technologies instead of equivalent pollutant ones or through the use of technologies to mitigate the negative impact of high emissions technologies. Pollutant abatement systems, carbon capture technologies, biobased products, etc. need to be established in order to make environmental parameters more and more similar to the pre-industrialization values of the planet Earth. In 15 papers international scientists addressed such topics, especially combining a high academic standard coupled with a practical focus on green processes and a quantitative approach to environmental impacts

Causes of persistent rural poverty in Thika district of Kenya, c.1953-2000

This study investigates the causes of poverty among the residents of Thika District in Kenya over the period 1953-2000. Using the articulation of modes of production perspective, the study traces the dynamics of poverty to the geography, history and politics of Thika District. The thrust of the argument is that livelihoods in the district changed during the period under investigation, but not necessarily for the better. Landlessness, collapse of the coffee industry, intergenerational poverty, and the ravages of diseases (particularly of HIV/AIDS) are analysed. This leads to the conclusion that causes of poverty in Thika District during the period under examination were complex as one form of deprivation led to another. The study established that poverty in Thika District during the period under review was a product of a process of exclusion from the centre of political power and appropriation. While race was the basis for allocation of public resources in colonial Kenya, ethnicity has dominated the independence period. Consequently, one would have expected the residents of Thika District, the home of Kenya’s first president, Mzee Jomo Kenyatta, to have benefited inordinately from public resources during his rule. Kenyatta’s administration, however, mainly benefited the Kikuyu elite. The study therefore demonstrates that during the period under examination, the Kikuyu, like any other Kenyan community, were a heterogeneous group whose differences were accentuated by class relations. Subaltern groups in Thika District therefore benefited minimally from state patronage, just like similar groups elsewhere in rural Kenya. By the late 1970s, the level of deprivation in rural Kenya had been contained as a result of favourable prices for the country’s agricultural exports. But in the subsequent period, poverty increased under the pressures of world economic recession and slowdowns in trade. The situation was worse for Kikuyu peasants as the Second Republic of President Daniel Moi deliberately attempted undermine the Kikuyu economically. For the majority of Thika residents, this translated into further marginalisation as the Moi regime lumped them together with the Kikuyu elite who had benefitted inordinately from public resources during the Kenyatta era. This study demonstrates that no single factor can explain the prevalence of poverty in Thika District during the period under consideration. However, the poor in the district devised survival mechanisms that could be replicated elsewhere. Indeed, the dynamics of poverty in Thika District represent a microcosm not just for the broader Kenyan situation but also of rural livelihoods elsewhere in the world. The study recommends land reform and horticulture as possible ways of reducing poverty among rural communities. Further, for a successful global war on poverty there is an urgent need to have the West go beyond rhetoric and deliver on its promises to make poverty history

TAKE IT TO THE SEA: NONMILITARY ACTORS IN CHINA’S MARITIME DISPUTES AND CRISIS MANAGEMENT

Two decades into the 21st century, China still faces a plethora of unsettled territorial and boundary disputes on its maritime frontier spanning from the Yellow Sea, East China Sea, and the South China Sea. These disputes cover strategically significant maritime space and involve U.S. treaty allies. As China’s power grows and it aspires to exert greater control over its periphery, how China handles local incidents arising from these disputes touches on the fundamental question of whether its rise will mean peace or instability for the region. There is a growing number of incidents arising from these disputes over the past twenty years, but China’s way of handling these incidents has varied widely. It has not always adopted an assertive, escalatory posture as its power continues to grow, nor has it invariably taken an accommodating, deescalatory posture as its good neighborly diplomacy strategy would suggest. When will China escalate an incident arising from its maritime disputes and when will it opt for deescalation? Should it choose to escalate, how does China calibrate its escalatory measures in terms of their nature (nonmilitary or military) and strength (restrained or forceful)? To account for the variation, this study develops a two-step theoretical framework to explain when, why, and how rising powers such as China choose to escalate or deescalate local incidents arising from unsettled maritime sovereignty and jurisdiction disputes. I argue that when deciding whether to escalate such incidents, leaders often simultaneously face two types of costs generated respectively by domestic and international audiences with oftentimes competing expectations, and thus a decision to escalate or deescalate entails a tradeoff between these two types of audience costs. Should China choose to escalate, it calibrates escalatory measures based on its assessment of one of the two criteria: the likelihood of being presented with a fait accompli by the adversary; or, should it have already been presented with a fait accompli during the crisis, the prospect of reversing it through negotiations. Several key findings emerge from this study. First, China has not been invariably prone to taking an escalatory posture in maritime disputes as its power grows. Rather, its decision of escalation or deescalation is a function of the interplay between the pulling and hauling among its domestic parochial interests on the one hand and Beijing’s assessment of China’s geopolitical environment on the other. Second, and counterintuitively, smaller countries can have substantial leverage over rising powers, contrasting the long-enshrined Thucydides dictum that “the strong do what they have the power to do and the weak accept what they have to accept.” China cares as much about its reputation for resolve as that for its image of nonbelligerency, suggesting that rising powers’ understanding of reputation is often two-pronged. Third, China has demonstrated a high level of sensitivity to the prospect of the adversary engaging in a fait accompli tactic. A fait accompli that China views as irreversibly altering the status quo, be that physically or nonphysically, can create strong motivations for China to undertake highly risky military escalation to compel for a reversal or compensate for its perceived losses