Balanced Configuration Research Articles

Performance modeling of a geophysics application to accelerate over‐decomposition parameter tuning through simulation

SummaryFinite‐difference methods are commonplace in High Performance Computing applications. Despite their apparent regularity, they often exhibit load imbalance that damages their efficiency. We characterize the spatial and temporal load imbalance of Ondes3D, a typical finite‐differences application dedicated to earthquake modeling. Our analysis reveals imbalance originating from the structure of the input data, and from low‐level CPU optimizations. Ondes3D was successfully ported to AMPI/CHARM++ using over‐decomposition and MPI process migration techniques to dynamically rebalance the load. However, this approach requires careful selection of the over‐decomposition level, the load balancing algorithm, and its activation frequency. These choices are usually tied to application structure and platform characteristics. In this article, we propose a workflow that leverages the capabilities of SimGrid to conduct such study at low experimental cost. We rely on a combination of emulation, simulation, and application modeling that requires minimal code modification and manages to capture both spatial and temporal load imbalance to faithfully predict the performance of dynamic load balancing. We evaluate the quality of our simulation by comparing simulation results with the outcome of real executions and demonstrate how this approach can be used to quickly find the optimal load balancing configuration for a given application/hardware configuration.

Robust entropy requires strong and balanced excitatory and inhibitory synapses.

It is widely appreciated that balanced excitation and inhibition are necessary for proper function in neural networks. However, in principle, balance could be achieved by many possible configurations of excitatory and inhibitory synaptic strengths and relative numbers of excitatory and inhibitory neurons. For instance, a given level of excitation could be balanced by either numerous inhibitory neurons with weak synapses or a few inhibitory neurons with strong synapses. Among the continuum of different but balanced configurations, why should any particular configuration be favored? Here, we address this question in the context of the entropy of network dynamics by studying an analytically tractable network of binary neurons. We find that entropy is highest at the boundary between excitation-dominant and inhibition-dominant regimes. Entropy also varies along this boundary with a trade-off between high and robust entropy: weak synapse strengths yield high network entropy which is fragile to parameter variations, while strong synapse strengths yield a lower, but more robust, network entropy. In the case where inhibitory and excitatory synapses are constrained to have similar strength, we find that a small, but non-zero fraction of inhibitory neurons, like that seen in mammalian cortex, results in robust and relatively high entropy.

Cyclic groups are CI-groups for balanced configurations

In this paper we propose an isomorphism criterion for cyclic balanced configurations defined over the same group $$\mathbb {Z}_n$$ . It is shown that two such configurations are isomorphic if and only if there exists a group automorphism of $$\mathbb {Z}_n$$ which maps one of the configurations onto the other. This result provides an easy isomorphism test for balanced cyclic configurations over the same cyclic group.

Simplified stress analysis of functionally graded single-lap joints subjected to combined thermal and mechanical loads

Functionally graded adhesive (FGA) joints involve a continuous variation of the adhesive properties along the overlap allowing for the homogenization of the stress distribution and load transfer, in order to increase the joint strength. The use of FGA joints made of dissimilar adherends under combined mechanical and thermal loads could then be an attractive solution. This paper aims at presenting a 1D-bar and a 1D-beam simplified stress analyses of such multimaterial joints, in order to predict the adhesive stress distribution along the overlap, as a function of the adhesive graduation. The graduation of the adhesive properties leads to differential equations which coefficients can vary the overlap length. For the 1D-bar analyses, two different resolution schemes are employed. The first one makes use of Taylor expansion power series (TEPS) as already published under pure mechanical load. The second one is based on the macro-element (ME) technique. For the 1D-beam analysis, the solution is only based on the ME technique. A comparative study against balanced and unbalanced joint configurations under pure mechanical and/or thermal loads involving constant or graduated adhesive properties are provided to assess the presented stress analyses. The mathematical description of the analyses is provided.

Influence of channel configuration on bandwidth of cadmium zinc telluride detector with a cross-strip pattern

The detector readout bandwidth is of paramount importance to achieve a high count rate and thus a high sensitivity. For detectors with the number of readout channels larger than that of the application-specific integrated circuit (ASIC), multiple ASICs are required. In systems with such a readout scheme, it is important to consider the load balance to achieve the highest count rate. In this work, a Monte Carlo simulation was performed to investigate the bandwidths of different load balancing configurations between two ASICs in a cross-strip cadmium zinc telluride detector. It is found that for anode strips, allocating each ASIC to half of the detector area provides a higher bandwidth when compared to allocating ASIC channels to alternate anode channels. Cathodes that are closer to the field of view will trigger more often and require a more complex load balancing scheme. Charge sharing and scattering play a role in the different bandwidths, and the bandwidth of the half-half configuration is 2.82% higher than that of the alternate configuration.

Capability configuration, ambidexterity and performance: Evidence from service outsourcing sector

How to resolve the dilemma of ambidexterity, or simultaneous alignment and adaption, is a vital issue in the operational field. Based on the resource management model, we argue that capability configurations could work as effective strategies for leveraging the potential of capabilities and benefit the pursuit of contradictory ambidexterity. This study explores how complementary and balance configurations of technological and marketing capabilities influence alignment and adaption and improve firm performance. Through regression analysis of data collected from service-outsourcing vendors in China, we provide evidence that both the complementary and balance configurations of these two capabilities can be used to achieve alignment and adaption, thereby improving firm performance. Moreover, whereas the complementary configuration of technological and marketing capabilities helps achieve alignment and adaption simultaneously, the balance configuration helps achieve only adaption. This study provides intriguing insights into resolving the dilemma of ambidexterity through exploiting the capability configuration strategy, which deserves scholars' attention in future studies.

300-GHz Balanced Varactor Doubler in Silicon CMOS for Ultrahigh-Speed Wireless Communications

This letter presents a 300-GHz varactor doubler suitable for ultrahigh-speed wireless communications. The doubler employs balance configuration to enhance the second harmonic efficiently. The proposed varactor doubler realized in TSMC 40-nm CMOS can be integrated with other CMOS components to generate millimeter-wave signals at 300-GHz frequency band. At the pumping frequency of 150 GHz and input power of 10 dBm, the doubler results in an output power of -4.6 dBm at 300 GHz. The doubler consumes no dc power while it occupies a chip area of 0.53 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> including probe pads.

Compact high‐speed envelope detector architecture for ultra‐wideband communications

AbstractThis article describes a Schottky diode based envelope detector architecture able to demodulate single‐ended signals adopting a single balanced configuration without the use of an external balun. The proposed architecture combines the functionality of a balun and, simultaneously, the rectification of the input signal. The dual functionality of the Schottky diodes applied, leads to a compact configuration that, according to the authors’ knowledge, has not been shown before. The manufactured prototype is able to demodulate error free a 2.5 Gbps amplitude shift keying signal at 8 GHz carrier frequency, achieving a bitrate to frequency carrier ratio (Δb) of 31.25%.

Bi-objective design of fresh food supply chain networks with reusable and disposable packaging containers

Abstract Packaging is crucial in protecting and handling products through the stages of their logistic networks. Actually, both disposable and reusable packaging containers are used. The former ends its life at the last stage of the distribution chain, the latter requires reverse flows to collect, recondition and, then, reuse it. Costs and emissions associated to the two types of packaging containers are different in nature, i.e. raw materials and landfill cost and emissions vs. reverse logistic costs and emissions, so that their choice is not univocal. Furthermore, such choice heavily affects the supply chain network structure and management. This paper addresses this topic aiming at designing a supply chain network including the packaging container best selection, storage/handling node location and flow allocation. An original bi-objective mixed integer linear programming model supports the decisional process. Despite the approach is general, a deep focus is on fresh fruit and vegetable distribution chain because of disposable and reusable packaging containers coexist in practice. The model looks at the cost and environmental impact minimisation over the whole network getting the Pareto frontier and supporting the logistic managers, industrial practitioners and policy makers in the network design and management. A real instance from Emilia-Romagna region, Italy, showcases the model application getting the economic and environmental optima together with best-balance configurations. Results stress the convenience of mixing reusable and disposable packaging containers to reach a global optimum. 47.1% reusable and 52.9% disposable is a possible good balance configuration reducing emissions while containing the cost increase.

Managing flood risks in the Mekong Delta: How to address emerging challenges under climate change and socioeconomic developments

Climate change and accelerating socioeconomic developments increasingly challenge flood-risk management in the Vietnamese Mekong River Delta—a typical large, economically dynamic and highly vulnerable delta. This study identifies and addresses the emerging challenges for flood-risk management. Furthermore, we identify and analyse response solutions, focusing on meaningful configurations of the individual solutions and how they can be tailored to specific challenges using expert surveys, content analysis techniques and statistical inferences. Our findings show that the challenges for flood-risk management are diverse, but critical challenges predominantly arise from the current governance and institutional settings. The top-three challenges include weak collaboration, conflicting management objectives and low responsiveness to new issues. We identified 114 reported solutions and developed six flood management strategies that are tailored to specific challenges. We conclude that the current technology-centric flood management approach is insufficient given the rapid socioecological changes. This approach therefore should be adapted towards a more balanced management configuration where technical and infrastructural measures are combined with institutional and governance resolutions. Insights from this study contribute to the emerging repertoire of contemporary flood management solutions, especially through their configurations and tailoring to specific challenges.

Stabilization of self-mode-locked quantum dash lasers by symmetric dual-loop optical feedback.

We report experimental studies of the influence of symmetric dual-loop optical feedback on the RF linewidth and timing jitter of self-mode-locked two-section quantum dash lasers emitting at 1550 nm. Various feedback schemes were investigated and optimum levels determined for narrowest RF linewidth and low timing jitter, for single-loop and symmetric dual-loop feedback. Two symmetric dual-loop configurations, with balanced and unbalanced feedback ratios, were studied. We demonstrate that unbalanced symmetric dual loop feedback, with the inner cavity resonant and fine delay tuning of the outer loop, gives the narrowest RF linewidth and reduced timing jitter over a wide range of delay, unlike single and balanced symmetric dual-loop configurations. This configuration with feedback lengths of 80 and 140 m narrows the RF linewidth by ∼ 4-67x and ∼ 10-100x, respectively, across the widest delay range, compared to free-running. For symmetric dual-loop feedback, the influence of different power split ratios through the feedback loops was determined. Our results show that symmetric dual-loop feedback is markedly more effective than single-loop feedback in reducing RF linewidth and timing jitter, and is much less sensitive to delay phase, making this technique ideal for applications where robustness and alignment tolerance are essential.

Equilibrium Analysis of Pin-Jointed Steel Structures under Large Variations of Configuration

In the paper an equilibrium analysis of pin-jointed steel structures is described. The attention is focused on the non-linearity problem that characterizes this type of steel structures under large displacements. A matrix method is developed, starting from a balanced and congruent configuration. Firstly, the analysis is conducted on the single bar; the, the behaviour of the global structure is analysed through the re-assembling and the final non-linear relationships between the variation of loads and the configuration are identified in order to proceed to the iterative solution path.

The university and the external environment – towards a collaborative system of resources exchange

Over the centuries, the role of universities and its impact on economic, social and cultural environment has changed. University relations with the main stakeholders: industry (business) and government have been changing from static and laissez faire to balanced configuration. The cooperation of these entities forms what we can call collaborative system of resources exchange. The main objective of collaboration with parties involved is to develop innovative solutions and to get the added value to each party. Value co-creation in a collaborative system depends on the ability to select and reconfigure individual elements in the way in which the emergence of new knowledge in a synergistic process takes place. University to meet the requirements of functioning in a collaborative system must adapt both its strategy (business model) and its internal processes. On the strategic level organizational culture based on dynamism of action, ability to take risks, willingness to change, ability to take advantage of opportunities, search for new ideas and innovation is of crucial importance. On operational level of crucial importance are relations between the process of knowledge production (research), the process of knowledge transfer (education), and the process of application of knowledge (innovation).

Design of Effective Control Schemes for Binary Distillation Columns

Distillation column is very important and high consuming energy equipment in oil refineries, such that 3% of the energy consumption in the world is allocated in distillation column. The fact that let controlling the distillation column an attractive field for researcher, and hence different control schemes are proposed by researchers. In this paper we will provide a comparative study between different control schemes for a binary distillation column two simple configurations (the most known ones) (LV&amp;DV) and two more complicated ones ((L/D,V/B) &amp; Ryskamp’s) we compare them in the basis of interactions and disturbance propagation. The mathematical models for the material balance configurations for the considered configurations are deduced using mathematical transformations (in the paper the general case of transformation between any two configurations is presented), taking the conventional configuration (LV) as a based configuration, the Dynamic Relative Magnitude Criterion (DRMC) is used to assess the interactions and disturbance propagation. The results show that the ratios control schemes are less sensitive to interactions compared with energy balance configuration LV. The same was noticed with DV configuration however other process drawbacks let it not recommended in industrial field.

Are nonsymmetric balanced configurations of four equal masses virtual or real?

Balanced configurations of N point masses are the configurations which, in a Euclidean space of high enough dimension, i. e., up to 2(N − 1), admit a relative equilibrium motion under the Newtonian (or similar) attraction. Central configurations are balanced and it has been proved by Alain Albouy that central configurations of four equal masses necessarily possess a symmetry axis, from which followed a proof that the number of such configurations up to similarity is finite and explicitly describable. It is known that balanced configurations of three equal masses are exactly the isosceles triangles, but it is not known whether balanced configurations of four equal masses must have some symmetry. As balanced configurations come in families, it makes sense to look for possible branches of nonsymmetric balanced configurations bifurcating from the subset of symmetric ones. In the simpler case of a logarithmic potential, the subset of symmetric balanced configurations of four equal masses is easy to describe as well as the bifurcation locus, but there is a grain of salt: expressed in terms of the squared mutual distances, this locus lies almost completely outside the set of true configurations (i. e., generalizations of triangular inequalities are not satisfied) and hence could lead most of the time only to the bifurcation of a branch of virtual nonsymmetric balanced configurations. Nevertheless, a tiny piece of the bifurcation locus lies within the subset of real balanced configurations symmetric with respect to a line and hence has a chance to lead to the bifurcation of real nonsymmetric balanced configurations. This raises the question of the title, a question which, thanks to the explicit description given here, should be solvable by computer experts even in the Newtonian case. Another interesting question is about the possibility for a bifurcating branch of virtual nonsymmetric balanced configurations to come back to the domain of true configurations.

Optimal joint load balancing and EDCA configuration of IEEE 802.11 wireless hotspots

SummaryWireless hotspots, ie, infrastructures composed of several IEEE 802.11 access points (APs), are today the most common solution in providing Internet access to a wide and rapidly changing population of users. According to common device implementation, stations establish associations with APs based on the measured strongest Received Signal Strength Indicator level. This usually leads to an uneven distribution of users to APs, increasing the chances of local network congestion. Load balancing (LB) solutions aim at mitigating this problem controlling the distribution of users. The LB algorithms enforce stations to associate with APs that manage a low number of users and/or that have a low traffic load. Usually, LB solutions do not consider traffic priorities or they assume some a priori quality of service (QoS) configuration for users.In this study, we propose a QoS‐LB solution based on the cell breathing technique with the goal of balancing the load in IEEE 802.11e Enhanced Distributed Channel Access (EDCA) Hotspots. The proposed algorithm explores the space of possible power/EDCA configurations by using a branch and bound approach that reduces the number of analyzed configurations and, hence, the time required to find the global optimal solution. The algorithm has been analytically defined and its performance evaluated through simulations and tests in a real test bed. The results prove that the proposed solution is effective in solving the optimal QoS‐LB configuration problem in WiFi hotspots of average size.

Model-Based Estimation of the Communication Cost of Hybrid Data-Parallel Applications on Heterogeneous Clusters

Heterogeneous systems composed of CPUs and accelerators sharing communication channels of different performance are getting mainstream in HPC but, at the same time, they show a complexity that makes it difficult to optimize the deployment of a data parallel application. Recent analytical tools such as Functional Performance Models, combined with advanced partitioning algorithms, manage to achieve a balanced configuration by distributing the workload unevenly, according to the performance of the different processing units. Unfortunately, such uneven distribution of the computation load leads to communication unbalances that, very often, render worthless the previous workload balancing efforts. Finding the optimal communication scheme without expensive testing on the executing platform requires an analytical approach to the estimation of the communication cost of different configurations of the application. With this goal in mind, we propose and discuss an extension of the $\tau$ -Lop communication performance model to cover heterogeneous architectures. In order to provide a quantitative assessment of this extended model, we conduct experiments with two representative computational kernels, the SUMMA algorithm and the 2D wave equation solver. The $\tau$ -Lop predictions are compared against the HLogGP model and the observed costs for a variety of configurations, hardware resources and problem sizes.

The characterisation and treatment of food waste for improvement of biogas production during anaerobic digestion – A review

Anaerobic digestion is one of the major biological-based technologies for converting organic waste to energy. The end-product of the process is the production of biogas that can be harvested as renewable energy and a nutrient-rich digestate that can be transformed as biofertiliser. Food waste varies seasonally and geographically, leading to a variation of biogas potential among different studies. There is still a lack of study on the relationship among the variation of food waste characteristic, its effect on the operational parameters and their inhibition value and its effect on the efficiency of the methods for improving biogas production. This paper reviews the anaerobic digestion of food waste in three sections: the characteristic of food waste reported in the literature, mono-digestion of food waste and co-digestion of food waste with other feedstocks. This review aims to relate the characteristics of food waste to biogas potential and to propose process improvement for enhanced biogas production. Food waste showed variation in terms of bromatological analysis, where the carbohydrates was reported to be around 11.8–74%, protein was 13.8–18.1% and lipid was 3.78–33.72%. The biogas yield for mono-digestion of food waste was 0.27–0.642 m3 CH4/kg VS and for the co-digestion of food waste with other substrates was 0.272–0.859 m3 CH4/kg VS. It has been concluded that the variation in the characteristic of food waste, in terms of physical and biochemical properties, can affect the efficiency of the applied treatment for process improvement, including nutrient balance, mechanical treatment, thermal treatment and two-stage configuration. Co-digestion remains an effective method for biogas production from food waste. Thermal treatment can significantly increase biogas production but excessive treatment can reduce the biodegradability of food waste. Mechanical treatment is more effective in treating waste rich in cellulosic material.

Integrated Care Policy in Ireland: A Comparative Review

Introduction: Literature reveals that integrated care is perceived to be the answer to the many issues faced by health systems in in the OECD. Research has also identified many difficulties in its implementation1. In Ireland, it has been observed that there is a disconnect between the trend of patient centred policy making and the organisational support available to health professionals and patients at the frontline in its implementation. Description of Policy context and Objective: The context for this paper is the introduction of integrated care in Ireland through the implementation of Community Health Organisations (CHOs) in 2015/16 as outlined in the report– Report and Recommendations of the Integrated Service Area Review Group’ also referred to as the Healy Report (HSE 2014). A similar policy development was introduced in Northern Ireland since 2011; with the development of an integrated health and social care policy (Transforming Your Care, Review of Health and Social Care, 2011). This paper reports on a comparative review of integrated health and social care policy in both Ireland and Northern Ireland and identifies themes that emerge from a comparative policy document analysis. It examines the contents and specific aspects of both sets of policy documents including; implementation plans, structures and governance arrangements and their potential influence on professional practice. This paper will serve as a contribution to a future study on the process of implementation of integrated care in the Republic of Ireland. Highlights: Northern Ireland has implemented structural integration of its health and social care since the 1970s. Existence of similarity in policy goals and objectives, the reform programmes, guiding principles and agenda’s set out in policy documents in Northern Ireland and Republic of Ireland. The Republic of Ireland runs a risk of facing the same policy issues observed in the Northern Ireland experience of implementation based on policy recommendations. Sufficient resources need to be in place in order to have sustainable integrated care in the Republic of Ireland. Transferability: This paper describes the relevance of Northern Ireland experience and serves as a useful guide to the implementation of integrated health and social care in the Republic of Ireland. onclusion: (Key findings, discussion and lesson learned) The main themes that emerged from the comparative review include; policy process, structural composition, governance, management and accountability, clarity of professional roles and policy goals, localism agenda and standardised pathways, frontline autonomy and decision making, stakeholder inclusion and configuration. Implementing integrated care is expensive, requires balanced configuration of management, structures and governance arrangements that supports exchange of information across professionals, shared services, involvement of users, promotion of strong working relationships and collaborations as well as more research in bridging gaps between policy aims and frontline professional practice which on the long run produces sustainable health delivery outcomes.

Extended flow algorithm for online reconfiguration of large‐scale distribution system with interconnected distributed generators

The interconnection of distributed generators (DGs) in a power system increases the difficulty of managing the system. The minimization of the voltage deviation by network reconfiguration is an important requirement for dealing with the issue. We had previously developed a reconfiguration technique, named the intelligent flow algorithm (IFA), for determining the optimum or suboptimum network configuration within a short computation time. In the present paper, we propose an extension of IFA, named the extended flow algorithm (EFA), for more effective determination of the optimal network configuration of a distribution system containing massive installations of DGs. EFA is a two‐stage method in which the configuration that produces uniform power supply, referred to as the balanced configuration, is first generated, and then used to seek the optimal configuration using an improved branch exchange approach. Accordingly, EFA is more simplified to improve its computation speed on large‐scale systems. The algorithm was tested by case studies of different test distribution systems in the MATLAB environment, and was confirmed to have high performance to cope with DG installations and large‐scale systems. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.