4 research outputs found
Hybrid conjugate gradient-BFGS methods based on Wolfe line search
No full textIn this paper, we present some hybrid methods for solving unconstrained optimization problems. These methods are defined using proper combinations of the search directions and included parameters in conjugate gradient and quasi-Newton method of Broyden–Fletcher–Goldfarb–Shanno (CG-BFGS). Their global convergence under the Wolfe line search is analyzed for general objective functions. Numerical experiments show the superiority of the modified hybrid (CG-BFGS) method with respect to some existing methods.
Mathematics Subject Classification (2010): 65K05, 90C26, 90C30.
Received 23 December 2019; Accepted 08 February 2020
New hybrid conjugate gradient method for nonlinear optimization with application to image restoration problems
No full textsummary:The conjugate gradient method is one of the most effective algorithm for unconstrained nonlinear optimization problems. This is due to the fact that it does not need a lot of storage memory and its simple structure properties, which motivate us to propose a new hybrid conjugate gradient method through a convex combination of and . We compute the convex parameter using the Newton direction. Global convergence is established through the strong Wolfe conditions. Numerical experiments show the superior efficiency of our algorithm to solve unconstrained optimization problem compared to other considered methods. Applied to image restoration problem, our algorithm is competitive with existing algorithms and performs even better when the level of noise in the image is significant
France's Algeria Policy (1988-1995): Discourse, Motives and Means
No full textFrance's Algeria Policy (1988-1995). Discourse, Motives and Means is a study of the French response to political upheavals in Algeria. The October 1988 riots in Algeria sparked off a fast-track democratisation process which was, however, rapidly brought to an end. Following Algeria's Winter 1991/92 first free parliamentary elections through which Islamism imposed itself as the most popular form of political change, a coup d'etat was staged by the Military -- the everlasting nucleus of power in Algeria. Since the coup d'dtat in January 1992 and the subsequent clobbering of the Islamist opposition, Algeria has foundered in a sea of violence. Until now, all political initiatives to bring back the country on the path of civil peace have failed.
Starting from the premise that France's long-run foreign policy objective has always been to preserve its rank as Algeria's "senior foreign partner", this study seeks
to determine what policy France implemented in order to achieve its goal in the context of Algeria's turmoil. The central finding brought to the fore in this thesis is that
France's Algeria policy was a shifting policy. From the 1992 coup d'dtat until the May 1995 French presidential elections, shifts in policy occurred both under the Left
and the Right. In successive stages, the socialist Cresson and Beregovoy governments as well as the right-wing Balladur government supported both "conciliation" and "eradication" in Algeria, which translated into varying degrees of support to the Algerian new rulers. France's shifts from supporting conciliation to backing eradication (January 1993) and from buttressing eradication to calling for conciliation (September 1994) are analysed in the light of three themes that permeate this study : discourse, motives and means
Устойчивое поведение потребителей: исследование через призму теории поколений
No full textPurpose: to present an author-designed methodology for measuring sustainable consumer behavior and the results of its practical evaluation for the verbal modelling of behavior of consumers of generations X, Y and z in conditions of unstable socio-economic and environmental systems.Methods: the study is grounded in the application of methods of content analysis of secondary information and statistical analysis of primary data. Results and implications of the research study are grounded in the use of the author-designed system of indicators of sustainable consumer behavior in the marketing study of the extent of manifestation of such behavior by consumers of generations X, Y, z on a representative sample of 1195 units who reside in more than 200 large cities in Russia.Results: the author-designed customized methodology for measuring sustainable consumer behavior that is grounded in a system of qualitative indicators, classified by clusters of interrelated objectives on sustainable societal development (socio-economic, social and socio-environmental), has been developed. The study findings enabled the authors to identify significant differences in indicators of sustainable behavior of consumers of different generations and to determine their proclivity to exhibit sustainable behavior in the future. The detected differences served as the basis for demonstration of both the verbal models of sustainable behavior of consumers of generations X, Y and z and the possibility to identify generational groups as large market segments for the purposes of differentiating sustainable marketing strategies.Сonclusions and Relevance: the results of testing of the author-designed methodology for measuring sustainable behavior of consumers from different generational groups confirmed the provisions of the generational theory on differences in their behavior, which manifested itself in differentiation of the contribution of consumers of the X, Y, z generations to achieving socio-economic, social and environmental objectives in the country through productive (destructive) behavioral patterns. Therefore, application of generational theory provisions will be instrumental in identifying large target market segments, corresponding to the generational groups with different profiles and models of sustainable behavior, which will require differentiated approach in sustainable marketing.Цель статьи – представить авторскую методику измерения устойчивого поведения потребителей и результаты ее апробации для вербального моделирования потребительского поведения представителей поколений X, Y и z в условиях нестабильности социально-экономических и природных систем.Методы или методология проведения работы: Исследование основано на применении методов контент-анализа вторичной информации и статистического анализа первичных данных. Результаты и выводы работы базируются на использовании авторской системы показателей устойчивого поведения потребителей в маркетинговом исследовании степени проявления подобного поведения потребителями поколений X, Y и z на репрезентативной выборке объемом 1195 элементов, при охвате более чем 200-та крупных городов России.Результаты работы. Разработана и апробирована авторская методика измерения устойчивого поведения потребителей на основе системы качественных показателей, классифицированных в блоки по вкладу в решение взаимосвязанных задач по устойчивому развитию общества: социально-экономических, социальных, социально-экологических. По результатам исследования выявлены существенные различия в устойчивом поведении потребителей из разных поколенческих групп, определена их готовность к проявлению устойчивого поведения в будущем. На основании выявленных различий представлены вербальные модели устойчивого поведения потребителей поколений X, Y и z, показана возможность выделения поколенческих групп в качестве крупных сегментов рынка для дифференцированных стратегий маркетинга устойчивости.Выводы. Результаты апробации авторской методики измерения устойчивого поведения потребителей из разных поколенческих групп подтвердили положения теории поколений о различиях в их поведении, что выразилось в дифференциации вклада потребителей поколений X, Y и z в решение социально-экономических, социальных и социально-экологических задач в стране за счет продуктивных (деструктивных) паттернов поведения. Применение теории поколений позволило выделить крупные целевые сегменты рынка, соответствующие поколенческим группам с разными моделями устойчивого поведения, что потребует дифференцированного подхода в маркетинге устойчивости
