Theory-based Scheme Research Articles

Rate-Adaptable Multitask-Oriented Semantic Communication: An Extended Rate–Distortion Theory-Based Scheme

Rate-Adaptable Multitask-Oriented Semantic Communication: An Extended Rate–Distortion Theory-Based Scheme

QoS-Aware Dispersed Dynamic Mapping of Virtual Sensors in Sensor-Cloud

In this paper, we study the problem of dynamic mapping of virtual sensors in sensor-cloud for provisioning high quality of Sensors-as-a-Service (Se-aaS) in the presence of multiple sensor-owners and heterogeneous sensor nodes. We divide this problem into two subproblems—optimal dispersed node selection and optimal data-rate distribution, and analyze that these problems are NP-complete. Hence, we propose a game theory-based online scheme, named QADMAP, to solve these two problems in polynomial time. For the optimal node selection problem, we design a dynamic coalition-formation game-based online scheme, while maximizing the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dispersion index</i> of the selected nodes. On the other hand, we propose an evolutionary game theory-based scheme for distributing the data-rate requirements of the services among the selected nodes, optimally. As per our knowledge, none of the existing works on dynamic mapping of virtual sensors considers the stochastic behavior of sensor-cloud for provisioning Se-aaS. From simulations, we observe that, using QADMAP, the energy consumption of the network reduces by 29.88-31.73 percent, thereby improving the QoS in terms of service availability by 11 percent and increasing the profit of the SCSP by 3.63-9.82 percent, compared to the existing benchmark schemes.

Joint computing and communication resource allocation for satellite communication networks with edge computing

Benefit from the enhanced onboard processing capacities and high-speed satellite-terrestrial links, satellite edge computing has been regarded as a promising technique to facilitate the execution of the computation-intensive applications for satellite communication networks (SCNs). By deploying edge computing servers in satellite and gateway stations, SCNs can achieve significant performance gains of the computing capacities at the expense of extending the dimensions and complexity of resource management. Therefore, in this paper, we investigate the joint computing and communication resource management problem for SCNs to minimize the execution latency of the computation-intensive applications, while two different satellite edge computing scenarios and local execution are considered. Furthermore, the joint computing and communication resource allocation problem for the computation-intensive services is formulated as a mixed-integer programming problem. A game-theoretic and many-to-one matching theory-based scheme (JCCRA-GM) is proposed to achieve an approximate optimal solution. Numerical results show that the proposed method with low complexity can achieve almost the same weight-sum latency as the Brute-force method.

Integrated cloud macro- and micro-physics schemes with kinetic treatment of condensation processes for global models

A new parameterization scheme was developed to remove the saturation adjustment assumption and resolve the condensation process in the grid-scale cloud macrophysics scheme to build an integrated cloud microphysics scheme for global climate models. By applying a saturation prediction equation with calculations based on cloud hydrometeor properties, supersaturation or subsaturation can be determined within the macrophysics scheme. This treatment provides the basis for condensation calculation and allows the Wegener–Bergeron–Findeisen process to be resolved explicitly to render a realistic liquid–ice partition in mixed-phase clouds. The cloud fraction scheme was modified based on physics principles to complement the condensation scheme. The new scheme's performance was examined by incorporating it into the Community Atmosphere Model version 5 (CAM5) single-column model to simulate a Tropical Warm Pool–International Cloud Experiment (TWP–ICE) case. The results revealed that grid-scale cloud properties are sensitive to the condensation process's treatment, and the new scheme can produce a more reasonable cloud fraction and liquid–ice partition than the original CAM5. The theory-based scheme developed in this study may provide insight for addressing consistency between the macrophysical and microphysical schemes in global climate models.

Energy–Latency Tradeoff for Computation Offloading in UAV-Assisted Multiaccess Edge Computing System

Unmanned aerial vehicles (UAVs) have been considered as a promising approach for providing additional computation capability and extensive coverage to ground mobile devices (MDs), especially in the scenario where the communication infrastructure is unavailable. This article investigates a UAV-assisted multiaccess edge computing system, where a number of ground MDs are served by a flying UAV and a ground base station, both of them are equipped with computation resources. The system aims to minimize the weighted cost of time latency and energy consumption, subject to the constraints on offloading decisions and resource competition. Since this problem is NP-hard, and the MDs are autonomous, we propose a game theory-based scheme to find the optimal solution and prove the existence of the Nash equilibrium. Meanwhile, we propose another two schemes as the benchmark to evaluate the efficiency and effectiveness of the game-theoretic solution. The simulation results show that the game-theoretic scheme is able to achieve a near-optimal performance, and the convergence time is also stable when the number of MDs increases.

A Framework of Topology-Transparent Scheduling Based on Polynomial Ring

Topology transparent scheduling (TTS) has been widely studied over the last two decades, which provides guaranteed throughput for each node in the network with only knowledge of global parameters. Leveraging different mathematical approaches, the existing TTSs briefly fall into three board categories: 1) the Galois field (GF)-based; 2) the combinatory-based; and 3) the number theory-based schemes. In this letter, a new scheme via the polynomial ring is proposed as a generalization of Chinese remainder theorem (CRT)-based TTS presented recently. It brings significant improvement over the theoretic bounds of both maximum nodal degree supported and frame length required. In addition, we prove that the proposed scheme is also a generic framework of both GF and CRT-based TTS.

A Density Functional Theory-Based Scheme to Compute the Redox Potential of a Transition Metal Complex: Applications to Heme Compound.

We estimated the redox potential of a model heme compound by using the combination of our density functionals with a computational scheme, which corrects the solvation energy to the normal solvent model. Among many density functionals, the LC-BOP12 functional gave the smallest mean absolute error of 0.16 V in the test molecular sets. The application of these methods revealed that the redox potential of a model heme can be controlled within 200 mV by changing the protonation state and even within 20 mV by the flipping of the ligand histidine. In addition, the redox potential depends on the inverse of the dielectric constant, which controls the surroundings. The computational results also imply that a system with a low dielectric constant avoids the charged molecule by controlling either the redox potential or the protonation system.

Applying Distributed Constraint Optimization Approach to the User Association Problem in Heterogeneous Networks.

User association has emerged as a distributed resource allocation problem in the heterogeneous networks (HetNets). Although an approximate solution is obtainable using the approaches like combinatorial optimization and game theory-based schemes, these techniques can be easily trapped in local optima. Furthermore, the lack of exploring the relation between the quality of the solution and the parameters in the HetNet [e.g., the number of users and base stations (BSs)], at what levels, impairs the practicability of deploying these approaches in a real world environment. To address these issues, this paper investigates how to model the problem as a distributed constraint optimization problem (DCOP) from the point of the view of the multiagent system. More specifically, we develop two models named each connection as variable (ECAV) and each BS and user as variable (EBUAV). Hereinafter, we propose a DCOP solver which not only sets up the model in a distributed way but also enables us to efficiently obtain the solution by means of a complete DCOP algorithm based on distributed message-passing. Naturally, both theoretical analysis and simulation show that different qualitative solutions can be obtained in terms of an introduced parameter which has a close relation with the parameters in the HetNet. It is also apparent that there is 6% improvement on the throughput by the DCOP solver comparing with other counterparts when . Particularly, it demonstrates up to 18% increase in the ability to make BSs service more users when the number of users is above 200 while the available resource blocks (RBs) are limited. In addition, it appears that the distribution of RBs allocated to users by BSs is better with the variation of the volume of RBs at the macro BS.

Bridging the Gap: Theory-Based Design of a Microsurgical Skills Course for Ophthalmology Residents

Although theory-based schemes for course design are widely used in educational settings, making use of cognitive theory in the design of surgical skills courses in ophthalmology is rare. The primary aim of this study is to describe the application of instructional design, an established theory-based approach in course design, to the development of a surgical skills course for ophthalmology residents. The secondary aim of this study is to assess the educational effect of this theory-based course. A 1-day skills course was designed according to Gagné׳s events of instruction model, which was employed as a template for the instructional sequence of learning steps. Skills acquisition following the implementation of the model was measured with precourse and postcourse assessments. Moorfields Eye Hospital organized the 1-day annual intermediate surgical skills course, which was hosted at the Royal College of Ophthalmologists' microsurgical skills laboratory. A total of 20 ophthalmology residents of Moorfields Eye Hospital participated in the study. A 1-day surgical skills course was formulated according to the instructional design principles outlined. The 4 objectives of the course (corneal suturing, corneal gluing, intravitreal injections, and eyelid suturing) were addressed in a parallel fashion as to allow for multiple objectives to be processed simultaneously, in the context of the instructional design sequence. Assessments demonstrated significant improvement in skills acquisition for the 4 course objectives. Instructional design is a valuable tool for planning effective surgical training courses as it is portable, allowing its application to a wide variety of outcomes and settings, and its terminology is simple and understandable to those working in clinical education.

Two-energy-gap preformed-pair scenario for cuprate superconductors: Implications for angle-resolved photoemission spectroscopy

We show how, within a preformed-pair scenario for the cuprate pseudogap, the nodal and antinodal responses in angle-resolved photoemission spectroscopy necessarily have very different temperature $T$ dependences. We examine the behavior and the contrasting $T$ dependences for a range of temperatures both below and above ${T}_{c}$. Previously, the distinct nodal and antinodal responses have provided strong support for the ``two-gap scenario'' of the cuprates in which the pseudogap competes with superconductivity. Instead, our theory supports a picture in which the pseudogap derives from pairing correlations, identifying the two-gap components with noncondensed and condensed pairs. Our calculations are based on a microscopic diagrammatic approach for addressing pairing correlations in a regime where the attraction is stronger than BCS and the coherence length is anomalously short. This many body theory-based scheme takes as a starting point the BCS ansatz for the ground-state wave function and incorporates finite temperature effects through coupled equations for the single particle and pair propagators (or $T$ matrix). It leads to reasonably good agreement with a range of different photoemission measurements in the moderately underdoped regime and we emphasize that here there is no explicit curve fitting. We briefly address the more heavily underdoped regime in which the behavior is more complex.

An Effective Transmission Network Expansion Cost Allocation Based on Game Theory

The expansion of transmission systems impacts many entities in the market environment. Each entity may fare better or worse as a result of congestion relief in the presence of new investments. Negatively affected firms exert their influence to prevent the expansion from taking place. The opposition of these firms and the lack of appropriate incentives results in insufficient investments in transmission assets. The network is being frequently used at its maximum limits, leading to economic inefficiencies and reduced reliability. Hence, there is a need for effective incentive schemes for network expansion. In this paper, we propose a game theory-based scheme for the allocation of transmission expansion costs among market entities. The allocation takes into account both the physical and economic impacts of the new transmission assets and the influence of each firm on the expansion decision. This is the first scheme designed to give all market participants explicit incentives to support the expansion. The application of the allocation solution to the Garver six-bus system is presented to illustrate the capabilities of the proposed method

Key concepts in a framework for analysing visual landscape character

A transparent and theory-based scheme for analysing visual character is presented. Based on a literature review, nine key visual concepts are identified: stewardship, coherence, disturbance, historicity, visual scale, imageability, complexity, naturalness and ephemera. The nine visual concepts are presented in a framework of four levels of abstraction, described through the concepts' visual dimensions, landscape attributes contributing to the concepts and potential visual indicators suggested for mapping and quantifying the concepts. Each of these concepts focuses on different aspects of the landscape important for visual quality, where visual quality is an holistic experience of them all. The visual concepts presented are used to describe different characteristics of visual landscapes, rather than presenting a normative value for visual quality. It is believed that this framework can be important for landscape assessment and the compilation of landscape character.

Information systems assessment in public service organisations

This paper presents a systematic method of assessing information systems (IS) projects in public service organisations. Specifically, it describes the construction and validation of a theory-based scheme that facilitates the analysis of organisational impacts associated with the introduction of IS in public organisations. The scheme was developed, applied, and refined from a study of 140 reports of information systems (ISs) projects that were introduced into public agencies' operations in the early 1990s. The scheme is practical for post and pre implementation evaluation. It is effective in measuring impacts derived from open-ended questionnaires, reports, and proposals. The scheme is useful to researchers and managers for the measurement, evaluation, and management of change associated with the introduction of IT.