Indirect Interdependencies Research Articles

An Investigation of Factors Influencing Tool Life in the Metal Cutting Turning Process by Dimensional Analysis

This article uses dimensional analysis to formulate the tool life in the turning process of metal cutting for small-lot production by considering the impacts of the most important parameters. The estimation of tool life specifies process efficiency, machining productivity, resource consumption, machining time, and cost. Many parameters influence tool life on the real shop floor in small-lot production. This literature review studies 29 parameters affecting tool life directly or indirectly. The results of this research are represented as a graph-based analysis in the form of a web of interdependencies and a relationship matrix. The relationship matrix illustrates the direct and indirect interdependencies of the parameters which influence tool life in the turning process. The graph visualizes the weight of the parameters for the estimation of tool life in small-lot production. A cause-and-effect diagram is extracted from the relationship matrix to study the parameters affecting tool life in small-lot production. A dimensional analysis is executed based on the cause-and-effect diagram in order to calculate the tool life. The functions of tool life involve the cutting conditions, tool and workpiece hardness, cutting force, and cutting temperature. The dimensional analysis shows that the cutting speed, feed rate, and workpiece hardness are the most effective factors impacting tool life in the turning process.

Applying the resource interaction approach to policy analysis – Insights from the antibiotic resistance challenge

This paper explores how the Resource Interaction Approach (RIA), namely the 4Rs model and the three settings of developing-producing-using, can be applied to complex policy analyses. We use the global sustainability challenge of antibiotic resistance as an example to define an agenda about how these analytical tools can frame and analyze such problems systematically. We find that these tools offer benefits to policymakers, including flexibility in framing problems, by selecting the focal resources and values to be prioritized, and the ability to visualize the direct and indirect interdependencies that enable or hinder value creation. Moreover, the RIA can point at the resource interfaces that need to change through specific policy interventions, as well as the potential network-level barriers to such changes. We also find that the RIA needs to be complemented by network-level analyses of deal structures and monetary flows in order to better capture the legal and financial dimensions of policy problems and solutions.

Achieving sustainable development goals: Fact or Fiction?

This study investigates the capacities of Iran as a developing country to attain the full meaning of sustainability and explores the achievability of the Sustainable Development Goals (SDGs) through a conceptual system dynamics (SD) model. From one perspective, investigating complex systems such as sustainable development requires research methods that take into account the dynamic interdependencies among the 17 SDGs. From another perspective, although achieving SDGs are a universal agenda for all nations, the evaluation of each country's accomplishments has to be based on its national capacities and challenges in the way of implementing these goals. Therefore, as a response to this research agenda, the presented conceptual SD model of sustainable development consists of 14 causal loops that highlight the direct and indirect interdependencies among the SDGs. Moreover, based on the proposed SD model, it is concluded that not only the obstacles in the way of attaining several SDGs in Iran, namely as 1) regional conflicts and environmental concerns, 2) internal conflicts of interests among key stakeholders, 3) sanctions, and 4) absence of updated data and credible evaluation mechanism, makes it impossible for the country to reach the preordained milestones of specific SDGs, but also they would eventually affect the achievements of other goals badly. Furthermore, the presented study reveals that I) SDG 9 and SDG 17, II) SDG 8, III) SDG 12, and IV) SDG 13, SDG 14, SDG 15, respectively have the highest influence on achieving the desired behavior of the system in the context of Iran. This study provides valuable insights to the local managers in Iran in designing a set of prioritized policies for mainstreaming the 2030 Agenda into national plans and for the policymakers in other developing countries, creates a profound understanding of the systematic relationships among SDGs.

Analytical Reliability Evaluation of Active Distribution Systems Considering Information Link Failures

With the growing study on the active distribution network, an objective and efficient reliability evaluation method for such cyber-physical systems (CPS) is urgently needed. In this paper, first considering the cyber transmission performance, a new method is proposed for efficient evaluation of cyber link validity based on frequency-time domain transformation. In order to quantify the indirect interdependencies of cyber failures, an unresponsiveness probability model for switches is established. Then, an innovative method is proposed by combining the equivalent method and the minimal path method. Finally, a test system is established to verify the effectiveness of the proposed method. This study is instrumental in informing the efficient planning of contemporary CPS-based distribution networks.

A hybrid risk prioritization approach in construction projects using failure mode and effective analysis

PurposeConstruction projects involve with various risks during all phases of project lifecycle. Failure mode and effective analysis (FMEA) is a useful tool for identifying and eliminating possible risk of failure modes (FMs) and improving the reliability and safety of systems in a broad range of industries. The traditional FMEA method applies risk priority number method (RPN) to calculate risk of FMs. RPN method cannot consider the direct and indirect interdependencies between the FMs and is not appropriate for complex system with numerous components. The purpose of this study is to propose an approach to consider interdependencies between FMs and also using fuzzy theory to consider uncertainties in experts' judgments.Design/methodology/approachThe proposed approach consist of three stages: the first stage of hybrid model used fuzzy FMEA method to identify the failure mode risks and derive the RPN values. The second stage applied Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL) method to determine the interdependencies between the FMs which are defined through fuzzy FMEA. Then, analytic network process (ANP) is applied in the third stage to calculate the weights of FMs based on the interdependencies that are generated through FDEMATEL method. Finally, weight of FMs through fuzzy FMEA and FDEMATEL–ANP are multiplied to generate the final weights for prioritization. Afterward, a case study for a commercial building project is introduced to illustrate proficiency of model.FindingsThe results showed that the suggested approach could reveal the important FMs and specify the interdependencies between them successfully. Overall, the suggested model can be considered as an efficient hybrid FMEA approach for risk prioritization.Originality/valueThe originality of approach comes from its ability to consider interdependencies between FMs and uncertainties of experts' judgments.

Reliability assessment of a cyber physical microgrid system in island mode

As cyber physical systems, microgrids (MGs), with distributed generations and energy management systems, can improve the reliability of power supply for customers in MGs. To quantify the reliability of isolated MGs, a cyber-physical assessment model is proposed. In this model, the circuit breakers and distributed energy resources are treated as the coupling elements between the cyber system and physical system, where the circuit breakers are uniquely modelled by using the Markov process theory based on the indirect interdependencies between cyber physical elements. For the cyber system, the reliability model of communication networks is formulated based on the link connectivity evaluation method. For the physical system, a system state generating method is presented to account for the optimal operation strategy, which considers the influence of the optimization strategy on the failure consequence analysis. With the proposed cyber and physical reliability models, the sequential Monte Carlo (SMC) simulation method is adopted to assess the reliability of islanded MGs. Simulations are carried out on a test system, and results verify the feasibility and effectiveness of proposed assessment method. Furthermore, one application of the proposed method is on the parameter setting of the cyber system, in terms of enhancing MGs reliability.

Effects of light-dark cycle on the spatial distribution and feeding activity of fish larvae of two co-occurring species (Pisces: Hypophthalmidae and Sciaenidae) in a Neotropical floodplain lake.

Most studies on mechanisms regulating fish larvae processes have focused on assessing the isolated effects of food distribution and feeding behavior. However, in natural ecosystems, fish larvae may strongly interact with zooplankton organisms in an array of complex, direct and indirect interdependencies. This study analyzed the spatial distribution, diet and feeding behavior of early stages of Hypophthalmus edentatus and Plagioscion squamosissimus, two fish species co-occurring in an isolated floodplain lake, during the light-dark cycle. Larvae fed more actively during dark periods (dusk and night) when they migrated toward the surface of the lake, and remained on the bottom and fed less during light periods (day and dawn). Cladocerans represented the most frequent prey in the diet of H. edentatus larvae. In turn, P. squamosissimus larvae initially preferred cladocerans and, as they developed, included calanoid copepods in the diet. Significant differences were detected in the frequencies of food items consumed during larval development, which could be related to a better ability of the most developed stages to explore the environment in search of other prey.

Reliability Assessment of Smart Grids Considering Indirect Cyber-Power Interdependencies

The operation of power systems now relies on extensive applications of digital communication systems, known as cyber networks. These applications are categorized as having either direct or indirect interactions between cyber and power networks. We previously studied direct interdependencies inside cyber-power networks and proposed the state mapping based model to evaluate its impact on the power system reliability. This paper focuses on indirect interdependencies between cyber and power networks. Certain applications of indirect interdependencies in modern power systems are discussed, and a state updating-based model is proposed to quantitatively evaluate the reliability of cyber-power networks under indirect interdependencies. Two optimization models are used to maximize the data connectivity in the cyber network and minimize the load curtailment in the power network. A high-voltage substation equipped with both monitoring and protection systems is studied to show the effectiveness of the proposed solution model.

Effects of resources and food web structure on bacterioplankton production in a tropical humic lagoon

The majority of studies of mechanisms regulating bacterioplankton processes havefocused on assessing the isolated effects of nutrients and predation. However, innatural ecosystems, microorganisms may interact strongly with larger organisms inan array of complex, direct and indirect interdependencies. In this work, wereport the results of a field mesocosm experiment in which, over 7 weeks, we eval-uated the individual and interactive effects of resource availability (N and Paddition) and indirect effects originating from the presence of an omnivorous fishspecies (Hyphessobrycon bifasciatus) on bacterioplankton production (BP). Nutrientaddition and fish presence both had individual positive effects on BP, but bottom-up control effects were stronger than indirect top-down control effects. The posi-tive effect of nutrients on BP was mainly direct, through increasing the availabilityof inorganic N and P. There was no significant interaction between fish and nutri-ents. The positive indirect top-down effects of omnivorous fish on BP were prob-ably related to both fish-mediated changes in the zooplankton communitystructure and fish-mediated cross-habitat nutrient regeneration. Our results showthat changes in food web structure, due to the presence or absence of vertebratemacroconsumers, can also affect heterotrophic microbial processes.KEYWORDS: trophic interactions; inorganic nutrients; omnivorous fish;microbial food web; enclosures

Pecuniary Knowledge Externalities: Evidence from European Regions

The paper investigates the effects of agglomeration and specialization of technological activities on regional productivity growth, applying the notion of pecuniary knowledge externalities. The latter are indirect interdependencies between firms mediated by the price system. Pecuniary knowledge externalities enable to appreciate both the positive and negative effects associated with the regional concentration of knowledge generating activities. Our analysis leads to specify the hypothesis of an inverted U-shaped relationship between the agglomeration of innovation activities and productivity growth. The empirical investigation, based upon 138 European regions in the years 1996 through 2003, supports the hypothesis that agglomeration yields diminishing positive net effects beyond a maximum. The homogeneity of knowledge generating activities however reduces absorption costs and hence rises the net benefits at each agglomeration level.

Partial Phase Synchronization for Multivariate Synchronizing Systems

Graphical models applying partial coherence to multivariate time series are a powerful tool to distinguish direct and indirect interdependencies in multivariate linear systems. We carry over the concept of graphical models and partialization analysis to phase signals of nonlinear synchronizing systems. This procedure leads to the partial phase synchronization index which generalizes a bivariate phase synchronization index to the multivariate case and reveals the coupling structure in multivariate synchronizing systems by differentiating direct and indirect interactions. This ensures that no false positive conclusions are drawn concerning the interaction structure in multivariate synchronizing systems. By application to the paradigmatic model of a coupled chaotic Roessler system, the power of the partial phase synchronization index is demonstrated.