--- For your convenience, this form can be processed by EasyChair --- automatically. You can fill out this form offline and then --- upload it to EasyChair. Several review forms can be uploaded --- simultaneously. You can modify your reviews as many times as --- you want. --- When filling out the review form please mind --- the following rules: --- (1) Lines starting with --- are comments. EasyChair will --- ignore them. Do not start lines in your review with --- --- as they will be ignored. You can add comments to the --- review form or remove them --- (2) Lines starting with *** are used by EasyChair. Do not --- remove or modify these lines. -------------------------------------------------------------- *** REVIEW FORM ID: 81540::51595 *** SUBMISSION NUMBER: 19 *** TITLE: A Discrete Binary Version of the Electromagnetism-Like Heuristic for Solving the Combinatorial Optimization Problems *** AUTHORS: Nikbakhsh Javadian, Mohsen Gol Alikhani and Reza Tavakkoli-Moghaddam *** PC MEMBER: Todd Wareham -------------------------------------------------------------- *** REVIEW: --- Please provide a detailed review, including justification for --- your scores. This review will be sent to the authors unless --- the PC chairs decide not to do so. This field is required. This paper proposes a discretized Electromagnetism-Like (EM) heuristic for solving combinatorial optimization problems. This heuristic modifies an existing EM heuristic by applying a variant of the discretization method previously applied to particle-swarm optimization systems. This heuristic is applied to the Traveling Salesman Problem (TSP), and in testing appears to perform better (in terms of closeness of solutions to optimal) than previous EM algorithms for TSP. This paper is well-organized and well-written; there are some minor grammatical errors (some of which are noted below), but these do not detract from understanding the paper. The heuristic is well-described, and the previous work on which it is based (and the precise nature of this relationship) is nicely and honestly described as well. The testing, though extensive and well-described, is not quite systematic enough to convince me of the magnitude of the improvement given by the new heuristic; however, it certainly does appear to perform better than previous EM algorithms in the cases examined. To summarize, this is a well-written paper describing a modification adopted from an existing heuristic algorithm of another heuristic algorithm that appears to result in improved performance, though the given testing does not firmly establish the magnitude of this improvement. Hence, I recommend neither acceptance nor rejection wrt COCOA. General comments: - Multiple citations should be in the same square brackets, i.e., replace "\cite{X} and \cite{Y}" by "\cite{X, Y}". - "... the continuous space ..." => "... continuous space ..." - What was the running times of the various EM algorithms described in this paper? How do these running times (and the qualities of obtained solutions) compare with those for non-EM heuristics for TSP? This should be mentioned in the Testing section (Section 5). Specific comments: - Title: ... Solving the Combinatorial ..." => "... Solving Combinatorial ..." - Abstract, last line: "... the previous ..." => "... algorithms in previous ..." - Page 1, paragraph 1, line 5: "... can be converged ..." => "... converges ..." - page 2, paragraph 2, line 5: "... Kennedy and Eberhardt ..." => "... Eberhardt and Kennedy ..." - page 2, paragraph 3, line 2: "... used in ..." => "... used to solve ..." - page 2, paragraph 3, last 2 lines: "... the TSP in large sizes." => "... large instances of TSP." - page 3, paragraph 1, last line: "... EM and ... step." => "... EM:" - page 4, paragraph 2, line 1: "In the ..." => "The ..." - page 4, paragraph 2, line 2: "... the premature ..." => "... premature ..." - page 4, end of paragraph 2: Is global convergence with probability one after an infinite / non-polynomial number of iterations? This should be clarified. - page 7, paragraph 1, last sentence: This statement is a bit strong -- Table 6 shows that for particular datasets, the instances cannot be solved exactly, but are solved fairly closely (especially by [5]). Perhaps it should be said that solution quality appears to drop as number of cities increases. This should be verified by (1) testing on instances with higher number of cities (preferably those instances used in the results described in Table 7) and (2) re-running the algorithms from [4] and [5] with higher numbers of iterations (comparable to those used in Table 7), especially for the larger inputs. The proposed EM should also be run on the test cases used in Table 6. Doing all this would allow a fairer comparison of all EM algorithms (how does the proposed discretized EM work on small instances? / can the older EM converge to better solutions if a comparable (for the proposed EM) number of iterations is allowed?) In addition, to verify that observed behavior holds for inputs of a particular size in general, more than one input of each size should be run and the average of the best solutions obtained for all instances of a given size should be graphed. - page 7, paragraph 2, line 7: Shouldn't 500 be 400 here (based on what I see in Table 7)? - page 8, paragraph 1, line 1: "... lager ..." => "... larger ..." - page 8: Figures 1 and 2 could collapse into one figure with 3 plot-lines. Even if this is not done, effort should be made to distinguish these lines (one dashed / one solid?), and "WU" should be replaced by "Wu" in the captions. -------------------------------------------------------------- *** REMARKS FOR THE PROGRAMME COMMITTEE: --- If you wish to add any remarks for PC members, please write --- them below. These remarks will only be used during the PC --- meeting. They will not be sent to the authors. This field is --- optional. -------------------------------------------------------------- --- If the review was written by (or with the help from) a --- reviewer different from the PC member in charge, add --- information about the reviewer in the form below. Do not --- modify the lines starting with *** *** REVIEWER'S FIRST NAME: (write in the next line) *** REVIEWER'S LAST NAME: (write in the next line) *** REVIEWER'S EMAIL ADDRESS: (write in the next line) -------------------------------------------------------------- --- In the evaluations below, uncomment the line with your --- evaluation or confidence. You can also remove the --- irrelevant lines *** OVERALL EVALUATION: --- 3 (strong accept) --- 2 (accept) --- 1 (weak accept) 0 (borderline paper) --- -1 (weak reject) --- -2 (reject) --- -3 (strong reject) *** REVIEWER'S CONFIDENCE: --- 4 (expert) --- 3 (high) 2 (medium) --- 1 (low) --- 0 (null) *** END -------------------------------------------------------------- -------------------------------------------------------------- --- For your convenience, this form can be processed by EasyChair --- automatically. You can fill out this form offline and then --- upload it to EasyChair. Several review forms can be uploaded --- simultaneously. You can modify your reviews as many times as --- you want. --- When filling out the review form please mind --- the following rules: --- (1) Lines starting with --- are comments. EasyChair will --- ignore them. Do not start lines in your review with --- --- as they will be ignored. You can add comments to the --- review form or remove them --- (2) Lines starting with *** are used by EasyChair. Do not --- remove or modify these lines. -------------------------------------------------------------- *** REVIEW FORM ID: 83931::51595 *** SUBMISSION NUMBER: 30 *** TITLE: Linear Ordering Problem Applications and Extensions *** AUTHORS: Philippe Mahey, Mourad Baiou and Abilio Lucena *** PC MEMBER: Todd Wareham -------------------------------------------------------------- *** REVIEW: --- Please provide a detailed review, including justification for --- your scores. This review will be sent to the authors unless --- the PC chairs decide not to do so. This field is required. This paper presents a collection of research proposals (two of which have associated algorithmic results) for the linear ordering problem, which has applications in economics. The two results are (1) a revised integer linear programming (ILP) formulation for the general problem (to aid in finding better exact solutions in general) and (2) an ILP formulation for a practically useful restricted version of the general problem, i.e., fixed-cardinality linear ordering. Both formulations are tested relative to existing benchmark datasets using the ILP solver CPLEX, and results are given and interpreted. Additional algorithms for solving both formulations are also briefly sketched. This paper is well-written and well-organized, the linear-ordering problem is defined clearly, and previous algorithms are summarized well. The proposals for additional algorithms also seem interesting. However, the paper would be much stronger to me if it more fully described and actually implemented the proposed algorithms for solving the given ILP formulations. As such, it seems much more a proposal of work to do rather than a summary of work done. To summarize, this is a well-written paper describing preliminary work. As such, I cannot recommend it for acceptance at COCOA. Specific comments: - Abstract, line 2: "It also ..." => "It ..." - Abstract, line 5: "Additionally, an ..." => "An ..." - Page 2: What is the computational complexity of the linear ordering problem? can it be solved exactly in polynomial time? If it NP-hard? I suspect the latter, but that should be clearly stated somewhere (with a citation to the literature backing this up). - Page 4, paragraph 2: What is a percentage duality gap? - Page 7, paragraph 2: More discussion of results might be appropriate here. Also, what are the instances xxx and yyy mentioned in the last line of this paragraph? -------------------------------------------------------------- *** REMARKS FOR THE PROGRAMME COMMITTEE: --- If you wish to add any remarks for PC members, please write --- them below. These remarks will only be used during the PC --- meeting. They will not be sent to the authors. This field is --- optional. -------------------------------------------------------------- --- If the review was written by (or with the help from) a --- reviewer different from the PC member in charge, add --- information about the reviewer in the form below. Do not --- modify the lines starting with *** *** REVIEWER'S FIRST NAME: (write in the next line) *** REVIEWER'S LAST NAME: (write in the next line) *** REVIEWER'S EMAIL ADDRESS: (write in the next line) -------------------------------------------------------------- --- In the evaluations below, uncomment the line with your --- evaluation or confidence. You can also remove the --- irrelevant lines *** OVERALL EVALUATION: --- 3 (strong accept) --- 2 (accept) --- 1 (weak accept) --- 0 (borderline paper) -1 (weak reject) --- -2 (reject) --- -3 (strong reject) *** REVIEWER'S CONFIDENCE: --- 4 (expert) --- 3 (high) 2 (medium) --- 1 (low) --- 0 (null) *** END --------------------------------------------------------------