Symmetric duality in complex spaces over cones

Duality theory plays an important role in optimization theory. It has been extensively used for many theoretical and computational problems in mathematical programming. In this paper duality results are established for first and second order Wolfe and Mond-Weir type symmetric dual programs over general polyhedral cones in complex spaces. Corresponding duality relations for nondifferentiable case are also stated. This work will also remove inconsistencies in the earlier work from the literature.

Optimality conditions and duality for multiobjective semi-infinite programming with data uncertainty via Mordukhovich subdifferential

Based on the notation of Mordukhovich subdifferential in [27], we propose some of new concepts of convexity to establish optimality conditions for quasi ?-solutions for nonlinear semi-infinite optimization problems with data uncertainty in constraints. Moreover, some examples are given to illustrate the obtained results.

A hybrid VNS matheuristic for a bin packing problem with a color constraint

We study a new variant of the bin packing problem with a color constraint. Given a finite set of items, each item has a set of colors. Each bin has a color capacity, the total number of colors for a bin is the unification of colors for its items and cannot exceed the bin capacity. We need to pack all items into the minimal number of bins. For this NP-hard problem we present approximability results and design a hybrid matheuristic based on the column generation technique. A hybrid VNS heuristic is applied to the pricing problem. The column generation method provides a lower bound and a core subset of the most promising bin patterns. Fast heuristics and exact solution for this core produce upper bounds. Computational experiments for test instances with number of items up to 500 illustrate the efficiency of the approach.

G-α-preinvex functions and non-smooth vector optimization problems

In this paper, we proposed the non-smooth G-?-preinvexity by generalizing ?-invexity and G-preinvexity, and discussed some solution properties about non-smooth vector optimization problems and vector variational-like inequality problems under the condition of non-smooth G-?-preinvexity. Moreover, we also proved that the vector critical points, the weakly efficient points and the solutions of the non-smooth weak vector variational-like inequality problem are equivalent under non-smooth pseudo-G-?-preinvexity assumptions.

Corrigendum on: Optimality conditions and duality for multiobjective semi-infinite programming with data uncertainty via Mordukhovich subdifferential (Yugoslav Journal of Operations Research, vol. 31, no 4, doi: https://doi.org/10.2298/YJOR201017013P)

The author of the article "Optimality Conditions and Duality for Multiobjective Semi-Infinite Programming with Data Uncertainity via Mordukhovich Subdifferential", Thanh-Hung Pham has informed the Editor about necessary corrections of the paper. <br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/YJOR201017013P">10.2298/YJOR201017013P</a></b></u>

A new type of difference I-convergent sequence in IFnNS

In this paper, we introduce the notion of a generalized difference I-convergent (i.e.?m-I-convergent) and difference I-Cauchy (i.e.?m-I-Cauchy) sequence in intuitionistic fuzzy n-normed spaces. Further, we prove some results related to this notion. Also, we study the concepts of a generalized difference I+-convergent (i.e.?m-I+-convergent) sequence in intuitionistic fuzzy n-normed spaces and show the relation between them.

Measuring software reliability under the influence of an infected patch

Patching service provides software firms an option to deal with the leftover bugs and is thereby helping them to keep a track of their product. More and more software firms are making use of this concept of prolonged testing. But this framework of releasing unprepared software in market involves a huge risk. The hastiness of vendors in releasing software patch at times can be dangerous as there are chances that firms release an infected patch. The infected patch (es) might lead to a hike in bug occurrence and error count and might make the software more vulnerable. The current work presents an understanding of such situation through mathematical modeling framework; wherein, the distinct behavior of testers (during in-house testing and field testing) and users is described. The proposed model has been validated on two software failure data sets of Tandem Computers and Brazilian Electronic Switching System, TROPICO R-1500.

Parametric optimization of friction stir welding of Al-Mg-Si alloy: A case study

Al-Mg-Si alloys have wide applications in industries such as aerospace, marine, automobile, construction. In this work, newly developed friction stir welding (FSW) was utilized for joining of AA6082-T6 alloy. The effect of major FSW process variables like rotational speed, traverse speed, and shoulder diameter of tool is studied over microstructural and mechanical characteristics of friction stir welded (FSWed) joints. Experimental design was done using Taguchi method (L9 orthogonal array). Three factors viz. rotational speed, welding speed, and diameter of tool shoulder were taken at three levels each. Mathematical modelling was developed in order to optimize the tensile strength of weld joints. Analysis of variance (ANOVA) was utilized to determine the percentage contribution of input variables. The results of present study exhibits that shoulder diameter, rotation, and welding speed of tool significantly affect the mechanical strength of FSWed joints.

Variant vacation queueing system with Bernoulli feedback, balking and server's states-dependent reneging

We consider a single server Markovian feedback queue with variant of multiple vacation policy, balking, server's states-dependent reneging, and retention of reneged customers. We obtain the steady-state solution of the considered queue based on the use of probability generating functions. Then, the closed-form expressions of different system characteristics are derived. Finally, we present some numerical results in order to show the impact of the parameters of impatience timers on the performance measures of the system.

Correction of thermographic images based on the minimization method of Tikhonov functional

The paper considers the method of correction of thermographic images (thermograms) obtained by recording in the infrared range of radiation from the surface of the object under study using a thermal imager. A thermogram with a certain degree of reliability transmits an image of the heat-generating structure inside the body. In this paper, the mathematical correction of images on a thermogram is performed based on an analytical continuation of the stationary temperature distribution as a harmonic function from the surface of the object under study towards the heat sources. The continuation is carried out by solving an ill-posed mixed problem for the Laplace equation in a cylindrical region of rectangular cross-section. To construct a stable solution to the problem, the principle of the minimum of the Tikhonov smoothing functional we used.