Pub Date : 2012-11-15DOI: 10.2174/1874243201206010009
Ugbebor O. Olabisi, Nwonye Chukwunoso
Protracted voters' waiting time is widely accepted to be a major impediment to voters' turnout at elections. This paper presents a queueing simulation-optimization based methodology for reducing voter waiting time at the polls. In many places, insufficient ballot materials and poll presiding officials, in combination with lengthy voting time and high voters' traffic, have caused long lines and disenfranchised voters who left without voting. Although the underlying simulation model employs a blend of queueing theory, discrete-event simulation, and optimization, the procedure offers a simplistic methodology, to be used by the typically nontechnical election official, without getting him involved in the intricacies and complexities involved in the modeling process. This paper focuses on methods to mitigate voters' waiting time at the polls and reduce the number of disenfranchised voters. Our simulation results can be used in planning a cost- effective election process that will produce expeditious elections. AMS MSC (2010): 60K25; 68M20; 90B22; 90B15; 37M05; 93C65; 91B12.
{"title":"Modeling and Analysis of the Queue Dynamics in the Nigerian Voting System","authors":"Ugbebor O. Olabisi, Nwonye Chukwunoso","doi":"10.2174/1874243201206010009","DOIUrl":"https://doi.org/10.2174/1874243201206010009","url":null,"abstract":"Protracted voters' waiting time is widely accepted to be a major impediment to voters' turnout at elections. This paper presents a queueing simulation-optimization based methodology for reducing voter waiting time at the polls. In many places, insufficient ballot materials and poll presiding officials, in combination with lengthy voting time and high voters' traffic, have caused long lines and disenfranchised voters who left without voting. Although the underlying simulation model employs a blend of queueing theory, discrete-event simulation, and optimization, the procedure offers a simplistic methodology, to be used by the typically nontechnical election official, without getting him involved in the intricacies and complexities involved in the modeling process. This paper focuses on methods to mitigate voters' waiting time at the polls and reduce the number of disenfranchised voters. Our simulation results can be used in planning a cost- effective election process that will produce expeditious elections. AMS MSC (2010): 60K25; 68M20; 90B22; 90B15; 37M05; 93C65; 91B12.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"302 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115650214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-28DOI: 10.2174/1874243201206010001
I. Husain, B. Ahmad, Z. Jabeen
In this paper two types of duals are considered for a class of variational problems involving higher order derivatives. The duality results are derived without any use of optimality conditions. One set of results is based on Mond- Weir type dual that has the same objective functional as the primal problem but different constraints. The second set of results is based on a dual of an auxiliary primal with single objective function. Under various convexity and generalized convexity assumptions, duality relationships between primal and its various duals are established. Problems with natural boundary values are considered and the analogs of our results in nonlinear programming are also indicated.
{"title":"On Multiobjective Duality For Variational Problems","authors":"I. Husain, B. Ahmad, Z. Jabeen","doi":"10.2174/1874243201206010001","DOIUrl":"https://doi.org/10.2174/1874243201206010001","url":null,"abstract":"In this paper two types of duals are considered for a class of variational problems involving higher order derivatives. The duality results are derived without any use of optimality conditions. One set of results is based on Mond- Weir type dual that has the same objective functional as the primal problem but different constraints. The second set of results is based on a dual of an auxiliary primal with single objective function. Under various convexity and generalized convexity assumptions, duality relationships between primal and its various duals are established. Problems with natural boundary values are considered and the analogs of our results in nonlinear programming are also indicated.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124180172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-12-20DOI: 10.2174/1874243201105010030
Hansuk Sohn, Dennis L. Bricker, T. Tseng
We present the mean value cross decomposition algorithm and its simple enhancement for the two-stage stochastic linear programming problem with complete recourse. The mean value cross decomposition algorithm employs the Benders (primal) subproblems as in the so-called "L-shaped" method but eliminates the Benders master problem for generating the next trial first-stage solution, relying instead upon Lagrangian (dual) subproblems. The Lagrangian multipliers used in defining the dual subproblems are in turn obtained from the primal subproblems. The primal subproblem separates into subproblems, one for each scenario, each containing only the second-stage variables. The dual subproblem also separates into subproblems, one for each scenario which contains both first- and second-stage variables, and additionally a subproblem containing only the first-stage variables. We then show that the substantial computational savings may be obtained by solving at most iterations only the dual subproblem with the first-stage variables and bypassing the termination test. Computational results are highly encouraging.
{"title":"Mean Value Cross Decomposition for Two-Stage Stochastic Linear Programming with Recourse","authors":"Hansuk Sohn, Dennis L. Bricker, T. Tseng","doi":"10.2174/1874243201105010030","DOIUrl":"https://doi.org/10.2174/1874243201105010030","url":null,"abstract":"We present the mean value cross decomposition algorithm and its simple enhancement for the two-stage stochastic linear programming problem with complete recourse. The mean value cross decomposition algorithm employs the Benders (primal) subproblems as in the so-called \"L-shaped\" method but eliminates the Benders master problem for generating the next trial first-stage solution, relying instead upon Lagrangian (dual) subproblems. The Lagrangian multipliers used in defining the dual subproblems are in turn obtained from the primal subproblems. The primal subproblem separates into subproblems, one for each scenario, each containing only the second-stage variables. The dual subproblem also separates into subproblems, one for each scenario which contains both first- and second-stage variables, and additionally a subproblem containing only the first-stage variables. We then show that the substantial computational savings may be obtained by solving at most iterations only the dual subproblem with the first-stage variables and bypassing the termination test. Computational results are highly encouraging.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129249538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-12-20DOI: 10.2174/1874243201105010039
Jen-Shiang Chen
This study considers a class of two-machine flow-shop scheduling problems with job delivery coordination. Both vehicle capacity and transportation times are also investigated. The objective is to minimize the mean arrival time of jobs. Two integer programming models are developed to optimally solve this problem. These two integer programming models are Models 1 and 2. Model 1 adopts the concept of assignment problem to formulate the proposed problems, while Model 2 bases on the dichotomous constraints models. Model 2 is theoretically better than Model 1 in size complexity analysis.
{"title":"Two-Machine Flow-Shop Scheduling with Job Delivery Coordination","authors":"Jen-Shiang Chen","doi":"10.2174/1874243201105010039","DOIUrl":"https://doi.org/10.2174/1874243201105010039","url":null,"abstract":"This study considers a class of two-machine flow-shop scheduling problems with job delivery coordination. Both vehicle capacity and transportation times are also investigated. The objective is to minimize the mean arrival time of jobs. Two integer programming models are developed to optimally solve this problem. These two integer programming models are Models 1 and 2. Model 1 adopts the concept of assignment problem to formulate the proposed problems, while Model 2 bases on the dichotomous constraints models. Model 2 is theoretically better than Model 1 in size complexity analysis.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124481038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-07-05DOI: 10.2174/1874243201105010019
A. Boulmakoul, M. Mandar
Pedestrian's studies are applied benefit and deployed in many areas; including public trip planning, and human factors analysis for building evacuation, or other situations where masses of people gather such as sporting events, etc. In this paper we describe a simulation system for virtual pedestrians. We mix the concept of fuzzy ant given by Ant Colony paradigm and associated cellular automaton model. We have adopted a fuzzy model for its particular ability to better represent uncertainty and imprecision about space perception. In our model we use it to represent virtual pedestrian's fuzzy pedestrian's desirability or visibility. A software solution was developed for this purpose. The Simulation results confirm predictions given by the first-order traffic flow theory. The proposed fuzzification is a preliminary step to consider other factors. The given system in its deployment phase will be integrated for pedestrians' accidents analysis in urban transportation networks. The strength of our model takes advantage in using explicit Ant Colony model and on projecting fuzzy theory to apprehend pedestrians' perceptions.
{"title":"Fuzzy Ant Colony Paradigm for Virtual Pedestrian Simulation","authors":"A. Boulmakoul, M. Mandar","doi":"10.2174/1874243201105010019","DOIUrl":"https://doi.org/10.2174/1874243201105010019","url":null,"abstract":"Pedestrian's studies are applied benefit and deployed in many areas; including public trip planning, and human factors analysis for building evacuation, or other situations where masses of people gather such as sporting events, etc. In this paper we describe a simulation system for virtual pedestrians. We mix the concept of fuzzy ant given by Ant Colony paradigm and associated cellular automaton model. We have adopted a fuzzy model for its particular ability to better represent uncertainty and imprecision about space perception. In our model we use it to represent virtual pedestrian's fuzzy pedestrian's desirability or visibility. A software solution was developed for this purpose. The Simulation results confirm predictions given by the first-order traffic flow theory. The proposed fuzzification is a preliminary step to consider other factors. The given system in its deployment phase will be integrated for pedestrians' accidents analysis in urban transportation networks. The strength of our model takes advantage in using explicit Ant Colony model and on projecting fuzzy theory to apprehend pedestrians' perceptions.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116700187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-20DOI: 10.2174/1874243201105010001
Tripathy Pk, M. Pattnaik
This paper focuses on an optimal disposal mechanism by extending the work of Tripathy et al. (11) to consider the system cost as fuzzy under flexibility and reliability criteria. It has been observed that by using a non-random optimization technique the derived disposal plan may result in no substantial difference in the system cost between the crisp and fuzzy model. Various numerical analyses demonstrate the effectiveness of proposed method. The results of the best order size obtained by the robust study are in general, very satisfactory. Finally through numerical examples sensitivity analysis show the influence of key model parameters. Based on consistency study, fuzzy strategy is better off than that of fixed cost strategy. Through sensitivity and robust analysis the results indicate that the performance of the proposed approach is superior to that of its crisp model. AMS (2000) Subject classification No: 90B05.
{"title":"A Non-Random Optimization Approach to a Disposal Mechanism Under Flexibility and Reliability Criteria","authors":"Tripathy Pk, M. Pattnaik","doi":"10.2174/1874243201105010001","DOIUrl":"https://doi.org/10.2174/1874243201105010001","url":null,"abstract":"This paper focuses on an optimal disposal mechanism by extending the work of Tripathy et al. (11) to consider the system cost as fuzzy under flexibility and reliability criteria. It has been observed that by using a non-random optimization technique the derived disposal plan may result in no substantial difference in the system cost between the crisp and fuzzy model. Various numerical analyses demonstrate the effectiveness of proposed method. The results of the best order size obtained by the robust study are in general, very satisfactory. Finally through numerical examples sensitivity analysis show the influence of key model parameters. Based on consistency study, fuzzy strategy is better off than that of fixed cost strategy. Through sensitivity and robust analysis the results indicate that the performance of the proposed approach is superior to that of its crisp model. AMS (2000) Subject classification No: 90B05.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130830593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-06-22DOI: 10.2174/1874243201004010012
H. Crauwels, B. Verlinden, D. Cattrysse, D. Oudheusden
Sheet-metal parts typically follow a unidirectional flow in the sheet-metal shop. In the first cutting stage, a large sheet is cut to different unfolded parts with a laser cutting machine. To avoid waste material different parts are combined on a sheet. Next, the 2D parts are transformed to 3D products with air bending. In this bending stage, time- consuming set-ups between production layouts are reduced as much as possible. Separate optimisation of cutting and air bending causes the optimisation benefits to counteract one another. Integrated models have been proposed for both single- and multiple-machine classes, but calculation times are too high and avoidable changeovers still occur. In this paper, by applying variable neighbourhood search with a number of different starting solutions, local optima of good quality are determined for minimising the makespan and the total flow time for both the single-machine and the multi-machine classes. Because the two performance measures are important for a good production plan, bicriteria optimisation by means of a simultaneous and a hierarchical approach, is also considered. Compared to the mathematical programming models for the combined cutting and bending operations, both quality and required computation time are improved for several real-life instances.
{"title":"Sheet-Metal Shop Scheduling Considering Makespan and Flow Time Criteria","authors":"H. Crauwels, B. Verlinden, D. Cattrysse, D. Oudheusden","doi":"10.2174/1874243201004010012","DOIUrl":"https://doi.org/10.2174/1874243201004010012","url":null,"abstract":"Sheet-metal parts typically follow a unidirectional flow in the sheet-metal shop. In the first cutting stage, a large sheet is cut to different unfolded parts with a laser cutting machine. To avoid waste material different parts are combined on a sheet. Next, the 2D parts are transformed to 3D products with air bending. In this bending stage, time- consuming set-ups between production layouts are reduced as much as possible. Separate optimisation of cutting and air bending causes the optimisation benefits to counteract one another. Integrated models have been proposed for both single- and multiple-machine classes, but calculation times are too high and avoidable changeovers still occur. In this paper, by applying variable neighbourhood search with a number of different starting solutions, local optima of good quality are determined for minimising the makespan and the total flow time for both the single-machine and the multi-machine classes. Because the two performance measures are important for a good production plan, bicriteria optimisation by means of a simultaneous and a hierarchical approach, is also considered. Compared to the mathematical programming models for the combined cutting and bending operations, both quality and required computation time are improved for several real-life instances.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131432701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-11DOI: 10.2174/1874243200903010001
G. Lesaja
In recent years the introduction and development of Interior-Point Methods has had a profound impact on optimization theory as well as practice, influencing the field of Operations Research and related areas. Development of these methods has quickly led to the design of new and efficient optimization codes particularly for Linear Programming. Consequently, there has been an increasing need to introduce theory and methods of this new area in optimization into the appropriate undergraduate and first year graduate courses such as introductory Operations Research and/or Linear Programming courses, Industrial Engineering courses and Math Modeling courses. The objective of this paper is to discuss the ways of simplifying the introduction of Interior-Point Methods for students who have various backgrounds or who are not necessarily mathematics majors.
{"title":"Introducing Interior-Point Methods for Introductory Operations Research Courses and/or Linear Programming Courses","authors":"G. Lesaja","doi":"10.2174/1874243200903010001","DOIUrl":"https://doi.org/10.2174/1874243200903010001","url":null,"abstract":"In recent years the introduction and development of Interior-Point Methods has had a profound impact on optimization theory as well as practice, influencing the field of Operations Research and related areas. Development of these methods has quickly led to the design of new and efficient optimization codes particularly for Linear Programming. Consequently, there has been an increasing need to introduce theory and methods of this new area in optimization into the appropriate undergraduate and first year graduate courses such as introductory Operations Research and/or Linear Programming courses, Industrial Engineering courses and Math Modeling courses. The objective of this paper is to discuss the ways of simplifying the introduction of Interior-Point Methods for students who have various backgrounds or who are not necessarily mathematics majors.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128253884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-10-07DOI: 10.2174/1874243200802010051
F. Strozzi, C. Noe, J. Zaldívar
The bullwhip effect refers to the phenomenon of demand distortion in a supply chain. By eliminating or con- trolling this effect, it is possible to increase product profitability. The main focus of this work is to apply a control tech- nique, based on the divergence of system, to reduce the bullwhip effect in a single-product one echelon supply chain, in which an Order-Up-To (OUT) order policy is applied. First the relationships between bullwhip, stability of the supply chain and the total costs are analyzed. Second the divergence-based control strategy is applied to stabilize the supply chain dynamics with a considerable reduction of the total costs (> 30%) and, in relevant cases, of the bullwhip effect.
牛鞭效应是指供应链中的需求扭曲现象。通过消除或控制这种影响，就有可能提高产品的盈利能力。本文主要研究了基于系统散度的单产品一级供应链的牛鞭效应控制技术，并在此基础上采用了从上到出(order - up - to, OUT)订单策略。首先分析了牛鞭、供应链稳定性和总成本三者之间的关系。其次，应用基于发散的控制策略稳定供应链动态，显著降低总成本(> 30%)，并在相关情况下降低牛鞭效应。
{"title":"Stability Control in a Supply Chain: Total Costs and Bullwhip Effect Reduction","authors":"F. Strozzi, C. Noe, J. Zaldívar","doi":"10.2174/1874243200802010051","DOIUrl":"https://doi.org/10.2174/1874243200802010051","url":null,"abstract":"The bullwhip effect refers to the phenomenon of demand distortion in a supply chain. By eliminating or con- trolling this effect, it is possible to increase product profitability. The main focus of this work is to apply a control tech- nique, based on the divergence of system, to reduce the bullwhip effect in a single-product one echelon supply chain, in which an Order-Up-To (OUT) order policy is applied. First the relationships between bullwhip, stability of the supply chain and the total costs are analyzed. Second the divergence-based control strategy is applied to stabilize the supply chain dynamics with a considerable reduction of the total costs (> 30%) and, in relevant cases, of the bullwhip effect.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133274809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-08-22DOI: 10.2174/1874243200802010044
D. Muñoz, D. Muñoz
In this article, we propose a theoretical framework to estimate performance measures in simulation experi- ments, incorporating both sample data from a random component and priors on input parameters of the simulation model. Our approach takes into account both the inherent uncertainty of the model as well as parameter uncertainty. We discuss the estimation of a conditional expectation under a Bayesian framework and point and variability estimators are proposed when direct sampling from the posterior distribution is not allowed. The application and properties of the proposed meth- odology are illustrated through an inventory model and simulation experiments using a Markovian model.
{"title":"A Bayesian Framework for the Incorporations of Priors and Sample Data in Simulation Experiments","authors":"D. Muñoz, D. Muñoz","doi":"10.2174/1874243200802010044","DOIUrl":"https://doi.org/10.2174/1874243200802010044","url":null,"abstract":"In this article, we propose a theoretical framework to estimate performance measures in simulation experi- ments, incorporating both sample data from a random component and priors on input parameters of the simulation model. Our approach takes into account both the inherent uncertainty of the model as well as parameter uncertainty. We discuss the estimation of a conditional expectation under a Bayesian framework and point and variability estimators are proposed when direct sampling from the posterior distribution is not allowed. The application and properties of the proposed meth- odology are illustrated through an inventory model and simulation experiments using a Markovian model.","PeriodicalId":337071,"journal":{"name":"The Open Operational Research Journal","volume":"41 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128482404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：