Deriving reservoir operating rules considering ecological demands of multiple stations

Reservoirs play important roles in hydropower generation, flood control, water supply, and navigation. However, the regulation of reservoirs is challenged due to their adverse influences on river ecosystems. This study uses ecoflow as an ecological indicator for reservoir operation to indicate the extent of natural flow alteration. Three reservoir optimization models are established to derive ecological operating rule curves. Model 1 only considers the maximization of average annual hydropower generation and the assurance rate of hydropower generation. Model 2 incorporates ecological objectives and constraints. Model 3 not only considers the hydropower objectives but also simulates the runoff and calculates the ecological indicator values of multiple downstream stations. The three models are optimized by a simulation-optimization framework. The reservoir ecological operating rule curves are derived for the case study of China's Three Gorges Reservoir. The results represent feasible schemes for reservoir operation by considering both hydropower and ecological demands. The average annual power generation and assurance rate of a preferred optimized scheme for Model 3 are increased by 1.06% and 2.50%, respectively. Furthermore, ecological benefits of the three hydrologic stations are also improved. In summary, the ecological indicator ecoflow and optimization models could be helpful for reservoir ecological operations.

From constraints to participation: A study of the behaviour of New Zealand travellers with mobility impairments

<p>Individuals with disabilities have been acknowledged in the literature to have the same desire to travel as their able-bodied counterparts. However, participation in tourism imposes disproportional challenges for many of them and there are still various areas that need to be improved. Research on travellers with disabilities is still in its infancy and most studies concentrate on barriers and constraints to participation. Not much is known about how these constraints are being dealt with and what influence they have on travel experiences of travellers with disabilities. This study explores the travel experiences of travellers with mobility impairments, with a focus on travel constraints and the negotiation strategies. This research draws upon the author’s personal experience as a traveller with mobility impairments who has faced travel constraints and tried to negotiate and overcome those constraints. I enjoy personal travel experiences and believe travel is a fundamental right for those with disabilities. Using an approach based on the social model of disability enhanced with a degree of human agency, this research was undertaken with travellers who have some degree of privileged status in terms of access to opportunities and resources required for travel. They voice concerns and problems, but they also demonstrate human agency which is significant for their travel experiences. The study seeks better insight into the tension between travel constraints and the ability of travellers with mobility impairments to participate in tourism. Constraints, negotiation strategies, and their influence on participation are addressed across different scales: the intrapersonal, interpersonal, and structural. A qualitative methodology informed by an interpretive social sciences paradigm enables this study to access people’s experiences expressed in their own words, give voice to them to get the meaning of social interactions, and thereby explain their travel experiences. Fourteen New Zealand-based participants aged between 18 and 44 were recruited, all of whom have either a congenital or acquired a mobility impairment. In-depth semi-structured interviews were designed with a staggered approach comprising three interview sessions with each participant. Overall, 42 interview sessions with 14 participants resulted in detailed data which was analysed using a content analysis approach. The analysis focused on the travel experiences of travellers with mobility impairments which span over degrees of participation: from non-participation to partial participation to full participation. This outlined the tension between constraints and negotiation and how the final levels of participation were impacted by that tension. Travel constraints, negotiation strategies, and tourism facilitators ‒ in three levels of intrapersonal, interpersonal, and structural ‒ affected the levels of participation. Sometimes participants used negotiation strategies from a different category than the constraint; for instance, an interpersonal negotiation strategy to overcome a structural constraint. The research confirmed many of the factors identified in the literature but revealed a greater range of constraints, facilitators and negotiation strategies, including some that have not previously been explored, for example, time (constraint), resilience and determination (facilitator), and developing emotional skills (negotiation strategy). The findings also revealed that some factors could influence participation with multiple roles. Equipment and money could be constraints, facilitators, and negotiation strategies in different travel experiences. Although generalized helplessness around travel was not observed in the sample, individual incidents of feeling a sense of helplessness had an effect on participation in tourism. Participants’ disability, more specifically the type and severity of their impairments, was another determining factor for participation. Lastly, the type of trip and destination were significant in terms of constraints encountered, negotiation strategies used, and the level of participation. Participants regarded business trips as the easiest (when compared to VFR and pleasure travel) with fewer constraints that generally were easier to overcome. Most participants also regarded domestic trips as easier compared to international trips due to their familiarity with the travel context. The research brings together the theory of negotiation, the theory of learned helplessness, and the leisure constraints model into a single study to understand different levels of participation among travellers with mobility impairments. Therefore, it contributes to an understanding of the travel experiences of travellers with mobility impairments in the New Zealand context and the implications of disabilities for travel. Hence, the research hopes to promote the changes required to improve the travel experiences of travellers with mobility impairments. Based on the theoretical and practical contributions of the study, several recommendations are provided for the tourism industry and the policy-makers. These recommendations aim at moving towards a more inclusive and fair tourism for travellers with disabilities.</p>

From constraints to participation: A study of the behaviour of New Zealand travellers with mobility impairments

<p>Individuals with disabilities have been acknowledged in the literature to have the same desire to travel as their able-bodied counterparts. However, participation in tourism imposes disproportional challenges for many of them and there are still various areas that need to be improved. Research on travellers with disabilities is still in its infancy and most studies concentrate on barriers and constraints to participation. Not much is known about how these constraints are being dealt with and what influence they have on travel experiences of travellers with disabilities. This study explores the travel experiences of travellers with mobility impairments, with a focus on travel constraints and the negotiation strategies. This research draws upon the author’s personal experience as a traveller with mobility impairments who has faced travel constraints and tried to negotiate and overcome those constraints. I enjoy personal travel experiences and believe travel is a fundamental right for those with disabilities. Using an approach based on the social model of disability enhanced with a degree of human agency, this research was undertaken with travellers who have some degree of privileged status in terms of access to opportunities and resources required for travel. They voice concerns and problems, but they also demonstrate human agency which is significant for their travel experiences. The study seeks better insight into the tension between travel constraints and the ability of travellers with mobility impairments to participate in tourism. Constraints, negotiation strategies, and their influence on participation are addressed across different scales: the intrapersonal, interpersonal, and structural. A qualitative methodology informed by an interpretive social sciences paradigm enables this study to access people’s experiences expressed in their own words, give voice to them to get the meaning of social interactions, and thereby explain their travel experiences. Fourteen New Zealand-based participants aged between 18 and 44 were recruited, all of whom have either a congenital or acquired a mobility impairment. In-depth semi-structured interviews were designed with a staggered approach comprising three interview sessions with each participant. Overall, 42 interview sessions with 14 participants resulted in detailed data which was analysed using a content analysis approach. The analysis focused on the travel experiences of travellers with mobility impairments which span over degrees of participation: from non-participation to partial participation to full participation. This outlined the tension between constraints and negotiation and how the final levels of participation were impacted by that tension. Travel constraints, negotiation strategies, and tourism facilitators ‒ in three levels of intrapersonal, interpersonal, and structural ‒ affected the levels of participation. Sometimes participants used negotiation strategies from a different category than the constraint; for instance, an interpersonal negotiation strategy to overcome a structural constraint. The research confirmed many of the factors identified in the literature but revealed a greater range of constraints, facilitators and negotiation strategies, including some that have not previously been explored, for example, time (constraint), resilience and determination (facilitator), and developing emotional skills (negotiation strategy). The findings also revealed that some factors could influence participation with multiple roles. Equipment and money could be constraints, facilitators, and negotiation strategies in different travel experiences. Although generalized helplessness around travel was not observed in the sample, individual incidents of feeling a sense of helplessness had an effect on participation in tourism. Participants’ disability, more specifically the type and severity of their impairments, was another determining factor for participation. Lastly, the type of trip and destination were significant in terms of constraints encountered, negotiation strategies used, and the level of participation. Participants regarded business trips as the easiest (when compared to VFR and pleasure travel) with fewer constraints that generally were easier to overcome. Most participants also regarded domestic trips as easier compared to international trips due to their familiarity with the travel context. The research brings together the theory of negotiation, the theory of learned helplessness, and the leisure constraints model into a single study to understand different levels of participation among travellers with mobility impairments. Therefore, it contributes to an understanding of the travel experiences of travellers with mobility impairments in the New Zealand context and the implications of disabilities for travel. Hence, the research hopes to promote the changes required to improve the travel experiences of travellers with mobility impairments. Based on the theoretical and practical contributions of the study, several recommendations are provided for the tourism industry and the policy-makers. These recommendations aim at moving towards a more inclusive and fair tourism for travellers with disabilities.</p>

An Integrated Fuzzy Goal Programming—Theory of Constraints Model for Production Planning and Optimization

Manufacturing companies are under constant pressure to optimize the economic sustainability of their production systems. Production planning and optimization is a well-established strategy for considering resource constraints and improving economic productivity. This study proposes an integrated fuzzy goal planning and the theory of constraints for production planning and optimization. To this end, a hybrid Delphi–Buckley method was used to identify the relevant goals and a paired matrix questionnaire was used to determine the fuzzy weights of the goals. Furthermore, a fuzzy bottleneck detection algorithm was used to deal with the bottlenecks. A case study in the cable industry is presented to demonstrate the applicability and exhibit the efficiency of the proposed model. The results indicate that production planning in the cable industry could experience less deviation, almost 11% less, from the goals by applying the fuzzy goal programming under the theory of constraints, compared to the traditional method or crisp-goal programming.

A Novel Constraints Model of Credibility-Fuzzy for Reliability Redundancy Allocation Problem by Simplified Swarm Optimization

A novel constraints model of credibility-fuzzy for the reliability redundancy allocation problem (RRAP) is studied in this work. The RRAP that must simultaneously decide reliability and redundancy of components is an effective approach in improving the system reliability. In practice various systems, the uncertainty condition of components used in the systems, which few studies have noticed this state over the years, is a concrete fact due to several reasons such as production conditions, different batches of raw materials, time reasons, and climatic factors. Therefore, this study adopts the fuzzy theory and credibility theory to solve the components uncertainty in the constraints of RRAP including cost, weight, and volume. Moreover, the simplified swarm optimization (SSO) algorithm has been adopted to solve the fuzzy constraints of RRAP. The effectiveness and performance of SSO algorithm have been experimented by four famous benchmarks of RRAP.

Determinants of Green Regeneration of Industrial Brownfield under Ecological Security Constraints: Model and Empirical Analysis Based on Grounded Theory

Green regeneration of industrial brownfields (GRIB) is an inevitable choice under the collision of industrial structure adjustment and ecological civilization construction. Due to vegetation destruction and industrial pollution, the integrity and health of the ecosystem in the industrial brownfield have been destroyed and ecological security has become a primary factor in restricting GRIB. In order to explore the impact mechanism of GRIB under ecological security constraints, based on the original data obtained from in-depth interviews with 21 professionals, this study examines the applicability of DPSIR model in GRIB by using the grounded theory method to sort the determinants and explore the impact mechanism of GRIB under ecological security constraints from five dimensions: driving forces (incentive factor), pressure (external factor), state (internal factor), influence (produced comprehensive result), and response (substantive response of human society). Suggestions are made to strengthen the investigation and remediation of environmental pollution in industrial brownfield, cultivate the concept and awareness of green regeneration, and formulate incentive policies. The research conclusions effectively improve the problems existing in the reconstruction of industrial brownfield as well as provide a theoretical basis and targeted reference for the promotion of GRIB.

Learning and Expertise in Mineral Exploration Decision-Making: An Ecological Dynamics Perspective

The declining discovery rate of world-class ore deposits represents a significant obstacle to future global metal supply. To counter this trend, there is a requirement for mineral exploration to be conducted in increasingly challenging, uncertain, and remote environments. Faced with such increases in task and environmental complexity, an important concern in exploratory activities are the behavioural challenges of information perception, interpretation and decision-making by geoscientists tasked with discovering the next generation of deposits. Here, we outline the Dynamics model, as a diagnostic tool for situational analysis and a guiding framework for designing working and training environments to maximise exploration performance. The Dynamics model is based on an Ecological Dynamics framework, combining Newell’s Constraints model, Self Determination Theory, and including feedback loops to define an autopoietic system. By implication of the Dynamics model, several areas are highlighted as being important for improving the quality of exploration. These include: (a) provision of needs-supportive working environments that promote appropriate degrees of effort, autonomy, creativity and technical risk-taking; (b) an understanding of the wider motivational context, particularly the influence of tradition, culture and other ‘forms of life’ that constrain behaviour; (c) relevant goal-setting in the design of corporate strategies to direct exploration activities; and (d) development of practical, representative scenario-based training interventions, providing effective learning environments, with digital media and technologies presenting decision-outcome feedback, to assist in the development of expertise in mineral exploration targeting.

Tracking Control of Autonomous Underwater Vehicles with Acoustic Localization and Extended Kalman Filter

The absence of global positioning system (GPS) signals and the influence of ocean currents are two of the main challenges facing the autonomy of autonomous underwater vehicles (AUVs). This paper proposes an acoustic localization-based tracking control method for AUVs. Particularly, three buoys that emit acoustic signals periodically are deployed over the surface. Times of arrivals of these acoustic signals at the AUV are then obtained and used to calculate an estimated position of the AUV. Moreover, the uncertainties involved in the localization and ocean currents are handled together in the framework of the extended Kalman filter. To deal with system physical constraints, model predictive control relying on online repetitive optimizations is applied in the tracking controller design. Furthermore, due to the different sampling times between localization and control, the dead-reckoning technique is utilized considering detailed AUV dynamics. To avoid using the highly nonlinear and complicated AUV dynamics in the online optimizations, successive linearizations are employed to achieve a trade-off between computational complexity and control performance. Simulation results show that the proposed algorithms are effective and can achieve the AUV tracking control goals.