Mode Selection Problem Research Articles

A fuzzy multi-criteria group decision making based on ranking interval type-2 fuzzy variables and an application to transportation mode selection problem

In this paper, we propose a fuzzy multi-criteria group decision-making method based on ranking interval type-2 fuzzy variables. First, we present a ranking method developed by relative preference index which we define using generalized credibility measure to rank interval type-2 fuzzy variables. Then, based on the proposed ranking method, we develop a new method to solve fuzzy multi-criteria group decision-making (FMCGDM) problems where linguistic ratings of the alternatives and the criteria weights are represented by interval type-2 fuzzy variables. The proposed FMCGDM method is applied to a transportation mode selection problem to find most preferable mode among available modes based on some selection criteria. The proposed method is simple in computation and important as it uses interval type-2 fuzzy variables which are more reasonable and sensible to represent linguistic terms rather than by type-1 fuzzy variables. A numerical experiment has been done to illustrate the proposed method.

Effects of carbon emission reduction policies on transportation mode selections with stochastic demand

We are witnessing more frequent extreme weather events due to the global warming. There is an urgent need for governments, industries, general public, and academics to take coordinated actions in order to tackle the challenges imposed by the climate change. It is essential to incorporate the environmental objective in the transportation mode selection problem as transportation is a main contributor to carbon emissions. With this in mind, our paper studies the retailer’s ordering and transportation mode selection problem using stochastic customer demand and investigates the optimal ordering and transportation mode selection decisions under different carbon emission reduction policies. Our analytical results reveal that there are some important transportation mode shifting thresholds under different carbon emissions reduction policies. These findings do not only help firms to make optimal decisions under different carbon emission reduction policies but also support policy makers to develop effective policies on carbon emissions reduction.

A Distributed Mode Selection Scheme for Device-to-Device Communications

The introduction of device-to-device (D2D) communication may provide higher energy efficiency and spectrum efficiency to the traditional cellular network. One important question coming out of this introduction is how to select the transmission mode for user equipment (UE). In this work, we investigate the mode selection problem in a distributed way which gives a rule for determining the transmitter to use cellular transmission or D2D transmission. Firstly, the link performances are analyzed for UE under cellular transmission mode and D2D transmission mode, respectively, and closed-form expressions are presented. Then the optimum mode selection metric is derived to maximize the successful transmission probability for the transmission link. Lastly, a distributed mode selection scheme is proposed which can determine the transmission mode by UE itself without frequent information exchanges. In addition, the link performance can be optimized by using this scheme. Simulation results show that the link performance is dependent on many wireless environment factors such as numbers of existing D2D links and cellular links, channel quality, decoding threshold at the receiver and power control. However, the optimum link performance can be achieved by the proposed scheme under these different deployment conditions and wireless environments. Compared with the random mode selection methods, the proposed scheme can at most improve the link performance by seven times .

Joint power allocation and mode selection for D2D communications with imperfect CSI

Device-to-device (D2D) communications can be underlaid with a cellular infrastructure to increase resource utilization, improve user throughput and save battery energy. In such networks, power allocation and mode selection are crucial problems. To address the joint optimization of power and mode selection under imperfect CSI, we propose an optimal, energy-aware joint power allocation and mode selection (JPAMS) scheme. First, we derive the closed-form solution for the power minimization for both D2D and cellular links while satisfying different quality of service (QoS) constraints. Second, we address the mode selection problem in presence of imperfect CSI, based on the derived power allocation. Moreover, the theoretical analysis and simulation results are presented to evaluate the proposed scheme for the D2D communications.

Optimal choice of standby modes in 1-out-of-N system with respect to mission reliability and cost

This paper considers a new type of optimization problems, the optimal standby mode selection problem in 1-out-of-N: G warm standby systems where multiple standby mode choices are available to provide different levels of operation readiness of standby elements and further to achieve a balance between fast restoration and low operation cost. Given the desired redundancy level and a fixed set of standby mode choices, the objective of the optimal system design is to choose a standby mode for each of redundant elements so as to minimize expected mission cost of the system subject to a certain reliability constraint. An iterative procedure is first suggested to evaluate system reliability and expected mission cost simultaneously. Based on the suggested evaluation algorithm, a genetic algorithm is then used as an optimization tool for solving the formulated optimal standby mode selection problem in 1-out-of-N: G warm standby systems. Examples are given to illustrate the considered evaluation and optimization problems as well as the proposed solution methodology.

Joint Mode Selection and Spectrum Partitioning for Device-to-Device Communication: A Dynamic Stackelberg Game

Device-to-device (D2D) communication technology is a promising add-on component for future wireless networks to provide local area services with increased spectrum efficiency and improved user experience. Three modes (i.e., cellular mode, reuse mode, and dedicated mode) can be used for D2D communication. A potential D2D user equipment (UE) can select a communication mode and dynamically adapt the mode selection according to the performance and the cost. This is referred to as the user-controlled mode selection problem. Also, a base station (BS) needs to reserve a spectrum band for the dedicated mode of operation, which we refer to as spectrum partitioning. The optimal spectrum partitioning needs to consider the utility of the BS that depends on the distribution of the users' mode selection, which, in turn, is governed by the spectrum partitioning. To jointly address the problems of spectrum partitioning and user-controlled mode selection (which are cyclically dependent on each other), we propose a dynamic Stackelberg game framework in which the BS and the potential D2D UEs act as the leader and the followers, respectively. Specifically, the adaptive mode selection of potential D2D UEs is formulated as a follower evolutionary game, and an evolutionary stable strategy is considered to be the solution. The dynamic control of spectrum partitioning by the BS is formulated as a leader optimal control problem. We also extend the formulation by considering information delays in control and state. Numerical analysis is performed to evaluate the effectiveness of the proposed framework, which shows that although the mode selection is performed in a distributed and user-controlled manner, the dynamic spectrum partitioning can be viewed as an effective incentive mechanism to drive the user distribution close to the optimal one.

Part-feeding with supermarket in assembly systems: transportation mode selection model and multi-scenario analysis

Purpose – The paper aims to focus on in-house part logistics design and management for assembly systems in which supermarket storage is adopted and coupled with an automated transportation system. In this context, this work aims to assess the transportation mode selection problem to speed up the preliminary design phase. Design/methodology/approach – The paper is divided into two main parts. The first one provides and discusses a new conceptual framework derived from the authors’ experience in the field and from previous published works. The framework aims to support managers in problem comprehension by setting three problem sub-phases, key input parameters and qualitative guidelines without losing sight of the big picture. The second part focuses on the transportation mode selection sub-phase by assessing an analytical study followed by a multi-scenario analysis. Findings – The final outcome of this work is a decision support matrix capable of setting technical guidelines that are helpful to managers and practitioners to speed up the transportation mode selection problem in the preliminary phases. Originality/value – This work is beneficial for supporting managers in understanding the main decisional steps involved in the design of a part-feeding system with a supermarket by discussing the three problem sub-phases and key input parameters and providing both qualitative and quantitative guidelines. Moreover, this study explores the transportation mode selection problem, which is not yet largely explored in the published literature.

A Novel Execution Mode Selection Scheme for Wireless Computing

Computation offloading is an effective way to alleviate the resource limited problem of mobile devices. However, the offloading is not an always advantageous strategy for under some circumstances the overhead in time and energy may turn out to be greater than the offloading savings. Therefore, an offloading decision scheme is in demand for mobile devices to decide whether to offload a computation task to the server or to execute it in a local processor. In this paper, the offloading decision problem is translated into a dynamic execution mode selection problem, the objective of which is to minimize the task execution delay and reduce the energy consumption of mobile devices. A novel execution mode adjustment mechanism is introduced to make the execution process more flexible for real-time environment variation. Numerical results indicate that the proposed scheme can significantly reduce the task execution delay in an energy-efficient way.

Joint Mode Selection and Resource Allocation for Device-to-Device Communications

Device-to-device (D2D) communications have been recently proposed as an effective way to increase both spectrum and energy efficiency for future cellular systems. In this paper, joint mode selection, channel assignment, and power control in D2D communications are addressed. We aim at maximizing the overall system throughput while guaranteeing the signal-to-noise-and-interference ratio of both D2D and cellular links. Three communication modes are considered for D2D users: cellular mode, dedicated mode, and reuse mode. The optimization problem could be decomposed into two subproblems: power control and joint mode selection and channel assignment. The joint mode selection and channel assignment problem is NP-hard, whose optimal solution can be found by the branch-and-bound method, but is very complicated. Therefore, we develop low-complexity algorithms according to the network load. Through comparing different algorithms under different network loads, proximity gain, hop gain, and reuse gain could be demonstrated in D2D communications.

Integrated location model with risk pooling and transportation mode selection

Location model with risk pooling and mode selection problems are integrated in this paper. Specifically, we consider a supply chain consisting of one supplier, distribution centres, transient points, and retailers who observe random demand that follows a certain probability distribution. Supplier dispatches the product to distribution centres using one mode of transportation while a given distribution centre may serve a retailer directly using one mode of transportation or through a transient point using two modes of transportation. The model is expected to determine facility location decisions, inventory decisions, and intermodal transportation decisions. The set of retailers who are assigned to a particular distribution centre are not known a priori. The derived model is large-scale and non-linear mixed integer programme. The difficulty of the model is reduced by adding a redundant constraint which made the solution procedure attainable. Also, Lagrangian relaxation approach is used to develop lower and upper limits on the optimal solution.

Research on the Selection of Logistics Service Innovation Mode Based on Industrial Clusters

Based on logistics industry clusters, the paper discusses innovation mode selection mechanism. Firstly, it expounds theories of logistics industry clusters. Then based on AHP, the key factors considered in the selection of innovation mode are used as the system of the measurement indexes, establish the AHP model, construct the judgment matrix and analyze data, obtain the weight coefficients of different logistics modes and do with consistency check. Finally, analyze results and make a conclusion. This method transfers the problem of qualitative into quantitative one and helps logistics clusters on mode selection problem of decision-making, thus contributes to innovation activities of logistics industry clusters.

Mode selection in pulsating stars

AbstractIn this review we focus on non-linear phenomena in pulsating stars: mode selection and amplitude limitation. Of many linearly excited modes, only a fraction is detected in pulsating stars. Which of them are excited, and why (the problem of mode selection), and to what amplitude (the problem of amplitude limitation) are intrinsically non-linear and still unsolved problems. Tools for studying these problems are briefly discussed and our understanding of mode selection and amplitude limitation in selected groups of self-excited pulsators is presented. We focus on classical pulsators (Cepheids and RR Lyrae stars) and main-sequence variables (δ Scuti and β Cephei stars). Directions of future studies are briefly discussed.

A Network Flow Approach to Throughput Maximization in Cooperative OFDMA Networks

In wireless cooperative orthogonal frequency-division multiple-access (OFDMA) networks, it is important to adapt the transmission strategies for each user according to the network channel dynamics in order to optimize the overall system performance. The adaption involves transmission mode selection (a user can choose from direct or cooperative transmission), subcarrier assignment, subcarrier pairing (the incoming and outgoing subcarriers at the relay for cooperative transmission need to be matched), relay selection, as well as power allocation and hence is highly challenging. Many previous works only consider a subset of the adaptation. In this paper, we tackle the joint optimization problem using a network flow approach. Specifically, we first show that for given power allocation, the combinatorial optimization problem of transmission mode selection, subcarrier assignment, relay selection and subcarrier pairing for the system total throughput maximization can be transformed into a minimum cost network flow (MCNF) problem with integer solutions. The linear optimal distribution (LOD) algorithm is applied to find the optimal solution in polynomial time. We then solve the mixed integer programming problem of the joint assignment and power allocation in an asymptotically optimal way in the dual domain. Simulation results show that the proposed algorithms can significantly enhance the overall system throughput.

Spectrum leasing and cooperative resource allocation in cognitive OFDMA networks

This paper considers a cooperative orthogonal frequency division multiple access (OFDMA)-based cognitive radio network where the primary system leases some of its subchannels to the secondary system for a fraction of time in exchange for the secondary users (SUs) assisting the transmission of primary users (PUs) as relays. Our aim is to determine the cooperation strategies among the primary and secondary systems so as to maximize the sum-rate of SUs while maintaining quality-of-service (QoS) requirements of PUs. We formulate a joint optimization problem of PU transmission mode selection, SU (or relay) selection, subcarrier assignment, power control, and time allocation. By applying dual method, this mixed integer programming problem is decomposed into parallel per-subcarrier subproblems, with each determining the cooperation strategy between one PU and one SU We show that, on each leased subcarrier, the optimal strategy is to let a SU exclusively act as a relay or transmit for itself. This result is fundamentally different from the conventional spectrum leasing in single-channel systems where a SU must transmit a fraction of time for itself if it helps the PU's transmission. We then propose a subgradient-based algorithm to find the asymptotically optimal solution to the primal problem in polynomial time. Simulation results demonstrate that the proposed algorithm can significantly enhance the network performance.

A fuzzy hierarchy integral analytic expert decision process in evaluating foreign investment entry mode selection for Taiwanese bio-tech firms

The purpose of this study is to help bio-tech firms solve the foreign investment (FI) entry mode selection problem. This study combines the concepts of factor analysis, analytic hierarchy process (AHP), genetic algorithm (GA), and fuzzy integral to construct an entry mode selection approach. This study produces several interesting findings. (1) In the different investment entry modes, there are large differences in evaluation focus when investors select their entry modes. (2) For example, Taiwanese bio-tech firms entering mainland China consider merger and acquisitions to be the first priority, and followed by strategic alliances. This research shows that if the stock share holding is unlimited, Taiwanese bio-tech firms prefer to select a high stock share holding investing mode. (3) In various investment modes, the aspects of “Capital and Risk” and “Technology Ability” have the most consistent effect on entry mode selection.

Deviation from the predicted wavenumber in a mode selection problem for the Turing patterns

In this paper, we investigate a mode selection problem for the Turing patterns generated from small random initial disturbances in one-dimensional reaction-diffusion systems on a sufficiently large domain. For this problem, it is widely accepted that the maximizer of the dispersion relation give rise to the wavenumber to be selected. Even in a small neighborhood of the bifurcation point, our numerical experiments show that this is not always true.

Damage evaluation of an axially loaded beam using modal flexibility

This work proposes a new nondestructive damage evaluation method that can detect, locate, and size damage by utilizing dynamically measured modal flexibility. The proposed method is particularly useful for a slender beam under an axial force. It belongs to the response-based approach because the response data are directly related to damage without the use of a numerical model. An equation governing the damage-mechanism is theoretically derived from modal flexibility. Solving the set of resulting equations provides the evaluation of damage. The accuracy of the proposed method is verified using a set of numerical simulatio ns. The proposed method attempts to resolve the mode selection problem, the singularity problem, the axial force problem, and the absolute severity estimation problem, all of which exist in earlier attempts. The proposed method is capable of conducting deta iled local inspections using incomplete measured modal parameters of a selected class of structures.

Nondestructive damage evaluation of a curved thin beam

A vibration-based nondestructive damage evaluation technique for a curved thin beam is introduced. The proposed method is capable of detecting, locating, and sizing structural damage simultaneously by using a few of the lower natural frequencies and their corresponding mode shapes before and after a small damage event. The proposed approach utilizes modal flexibilities reconstructed from measured modal parameters. A rigorous system of equations governing damage and curvature of modal flexibility is derived in the context of elasticity. To solve the resulting system of governing equations, an efficient pseudo-inverse technique is introduced. The direct inspection of the resulting solutions provides the location and severity of damage in a curved thin beam. This study confirms that there is a strong linear relationship between the curvature of modal flexibility and flexural damage in the selected class of structures. Several numerical case studies are provided to justify the performance of the proposed approach. The proposed method introduces a way to avoid the singularity and mode selection problems from earlier attempts.

Production and transport logistics scheduling with two transport mode choices

AbstractThis paper considers a new class of scheduling problems arising in logistics systems in which two different transportation modes are available at the stage of product delivery. The mode with the shorter transportation time charges a higher cost. Each job ordered by the customer is first processed in the manufacturing facility and then transported to the customer. There is a due date for each job to arrive to the customer. Our approach integrates the machine scheduling problem in the manufacturing stage with the transportation mode selection problem in the delivery stage to achieve the global maximum benefit. In addition to studying the NP‐hard special case in which no tardy job is allowed, we consider in detail the problem when minimizing the sum of the total transportation cost and the total weighted tardiness cost is the objective. We provide a branch and bound algorithm with two different lower bounds. The effectiveness of the two lower bounds is discussed and compared. We also provide a mathematical model that is solvable by CPLEX. Computational results show that our branch and bound algorithm is more efficient than CPLEX. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005

Damage estimation on beam-like structures using the multi-resolution analysis

This work proposes a vibration-based damage evaluation method that can detect, locate, and size damage utilizing only a few of the lower mode shapes. The proposed method is particularly advantageous for beam-like structures with uncertain applied axial load, mass density, and foundation stiffness. Based on a small damage assumption, a linear relationship between damaged and undamaged curvatures is revealed in the context of elasticity. It turns out that the resulting damage index equation inherently suffers from singularities near inflection nodes. The transformation of the problem into the multi-resolution wavelet domain provides a set of coupled linear equations. With the aid of the singular value decomposition technique, the solution to the damage index equation is achieved in the wavelet space. Next, the desired physical solution to the damage index equation is reconstructed from the one in the wavelet space. The performance of the proposed method is compared with two existing damage detection methods using a set of numerical simulations. The proposed method attempts to resolve the mode selection problem, the singularity problem, the axial force problem, and the absolute severity estimation problem, all of which remained unsolved by earlier attempts.