A D.C. Algorithm via Convex Analysis Approach for Solving a Location Problem Involving Sets

We study a location problem that involves a weighted sum of distances to closed convex sets. As several of the weights might be negative, traditional solution methods of convex optimization are not applicable. After obtaining some existence theorems, we introduce a simple, but effective, algorithm for solving the problem. Our method is based on the Pham Dinh - Le Thi algorithm for d.c. programming and a generalized version of the Weiszfeld algorithm, which works well for convex location problems

Minimal time functions and the smallest intersecting ball problem generated by unbounded dynamics

The smallest enclosing circle problem introduced in the 19th century by J. J. Sylvester [20] aks for the circle of smallest radius enclosing a given set of finite points in the plane. An extension of the smallest enclosing circle problem called the smallest intersecting ball problem was considered in [17,18]: given a finite number of nonempty closed subsets of a normed space, find a ball with the smallest radius that intersects all of the sets. In this paper we initiate the study of minimal time functions generated by unbounded dynamics and discuss their applications to extensions of the smallest intersecting ball problem. This approach continues our effort in applying convex and nonsmooth analysis to the well-established field of facility location

THÀNH PHẦN LOÀI VÀ PHÂN BỐ CỦA THÂN MỀM VÀ DA GAI RẠN SAN HÔ TRONG CHUYẾN KHẢO SÁT TRÊN TÀU VIỆN SĨ OPARIN NĂM 2016–2017

A study on the species composition and distribution of Mollusca and Echinodermata on coral reefs from Quang Tri to Binh Thuan was conducted during the field survey between Vietnam and Russia on the AKADEMIK OPARIN RC vessel in 2016 and 2017 at 39 reef stations. 150 species were identified belonging to 100 genera, 50 families, 22 orders, 7 classes distributed on coral reefs. The species composition of mollusca and echinodermata was different between study areas.Nghiên cứu về thành phần loài và phân bố của động vật thân mềm, da gai trên rạn san hô khu vực từ Quảng Trị đến Bình Thuận được thực hiện trong chuyến khảo sát hỗn hợp Việt - Nga trên tàu Viện sĩ OPARIN trong thời gian từ tháng 11 đến tháng 12/2016 và chuyến khảo sát bổ sung từ tháng 5 đến tháng 7/2017 tại 39 trạm rạn thuộc 10 vùng nghiên cứu. Bằng phương pháp hình thái so sánh, nhóm tác giả đã xác định được 150 loài động vật thân mềm và da gai thuộc 100 giống, 50 họ, 22 bộ, 7 lớp phân bố trên rạn san hô. Thành phần loài thân mềm và da gai tương đối khác biệt giữa các vùng nghiên cứu

Nonsmooth Algorithms and Nesterov\u27s Smoothing Technique for Generalized Fermat-Torricelli Problems

We present algorithms for solving a number of new models of facility location which generalize the classical Fermat--Torricelli problem. Our first approach involves using Nesterov\u27s smoothing technique and the minimization majorization principle to build smooth approximations that are convenient for applying smooth optimization schemes. Another approach uses subgradient-type algorithms to cope directly with the nondifferentiability of the cost functions. Convergence results of the algorithms are proved and numerical tests are presented to show the effectiveness of the proposed algorithms

Trends in socioeconomic inequalities in full vaccination coverage among vietnamese children aged 12–23 months, 2000–2014: Evidence for mitigating disparities in vaccination

There has been no report on the situation of socioeconomic inequalities in the full vaccination coverage among Vietnamese children. This study aims to assess the trends and changes in the socioeconomic inequalities in the full vaccination coverage among Vietnamese children aged 12–23 months from 2000 to 2014. Data were drawn from Multiple Indicator Cluster Surveys (2000, 2006, 2011, and 2014). Concentration index (CCI) and concentration curve (CC) were applied to quantify the degree of the socioeconomic inequalities in full immunization coverage. The prevalence of children fully receiving recommended vaccines was significantly improved during 2000–2014, yet, was still not being covered. The total CCI of full vaccination coverage gradually decreased from 2000 to 2014 (CCI: from 0.241 to 0.009). The CC increasingly became close to the equality line through the survey period, indicating the increasingly narrow gap in child full immunization amongst the poor and the rich. Vietnam witnessed a sharp decrease in socioeconomic inequality in the full vaccination coverage for over a decade. The next policies towards children from vulnerable populations (ethnic minority groups, living in rural areas, and having a mother with low education) belonging to lower socioeconomic groups may mitigate socioeconomic inequalities in full vaccination coverage. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Huy Nguyen” is provided in this record*