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1

Practical models of interconnections between content delivery networks and internet service providers

Cłapa Cezary, Lasoń Artur, Kanitkar Vinay, Chołda Piotr

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

|

2023

|

nr 4

395--398

EN

Content Delivery Networks (CDNs) play a key role in the Internet ecosystem. The continued growth of demand for services delivered online, as well as the increasing bandwidth disparity between its core and the last mile, strengthen their importance. A popular research problem related to CDN is the problem of deploying caching nodes. In this article, we present practical models of interconnection between Internet Service Providers (ISPs) and CDNs. We also enhance, with those models, an existing optimization model that approaches the mentioned problem. While presented interconnection models have a significant impact on the cost structure of the nodes and their scope of connectivity, they are not yet present in the literature.

PL

Sieci dystrybucji treści CDN (ang. Content Delivery Networks) odgrywają kluczową rolę w ekosystemie Internetu. Wzrost zapotrzebowania na usługi dostarczane online i postępująca dysproporcja przepustowości między jego siecią szkieletową, a ostatnią milą wzmacniają ich znaczenie. Popularnym zagadnieniem badawczym związanym z CDN jest problem rozmieszczenia węzłów buforujących. W tym artykule prezentujemy praktyczne modele połączeń między operatorami telekomunikacyjnymi (ang. Internet Service Provider, ISP), a operatorami CDN. Prezentujemy również wzbogacenie o nie przykładowego modelu optymalizacyjnego podejmującego wspominany problem. Modele te mają istotny wpływ na strukturę kosztu węzłów i ich zdolność zaspokajania zapotrzebowania na treści, jednak nie są obecne w literaturze.

2

Technical study of the installation of a watercress nectar processor to reduce anemia in adults

Manrique-Suarez Luis-Alberto, Ochoa-Sotomayor Nancy-Alejandra, Salazar-Robles Héctor-Gavino, Flores-Masías Edward José

Management Systems in Production Engineering

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2023

|

nr 1 (31)

59--70

EN

Peru has a diversity of exotic fruits and plants with recognized yields for food and health protection. Nectars are highly consumed food products, made from fruits or vegetables. The objective for the present work was to carry out the technical study of the installation of a watercress nectar processor to reduce anemia in adults; identify the demand, technical requirements for the operation and profitability of the processing facilities. Methodology. The analytical-synthetic method was used; The population of the target market was analyzed, the size of the sample was determined with the coefficient of variation method, (n = 384), the instrument used was the survey; the technical, economic-financial study was carried out. The results were the growth in the demand for nectars of 59.82%, with respect to the economic-financial evaluation, it has been shown that the results are satisfactory for the installation of the plant, with the economic and financial IRR, both rates proving to be attractive. for the project. From the projected income statement for the 2021-2025 period, it can be deduced that for 2025 there was a net profit of S/316,971.39. Other indicators such as the economic and financial NPV, the B/C ratio and the PRI that were satisfactory for the Project, making its execution viable. The conclusion this study was the technical study for the installation of a nectar processing plant to reduce anemia in adults in Lima, which was viable in terms of operation and profitability, taking advantage of its healing and nutritional properties.

3

Management of the workplaces by the facilities of operations research

Geseleva Nataliia, Proniuk Ganna, Romanyuk Olexander, Akimova Olga, Troianovska-Korobeynikova Tetiana, Savytska Liudmyla, Rakhmetullina Saule, Mekebayev Nurbapa

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2022

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T. 12, nr 3

69--73

EN

The optimal location of workplaces plays an important role in the structure of occupational safety. The design of the workspace should ensure the optimal distribution of functions between person and machine in order to create safe working conditions, reduce the severity of work and the level of production injuries. Most often, workplace planning is carried out manually, by simple calculation, and then the rationality of workplace planning is evaluated, based on statistics of industrial accidents and occupational diseases, as well as indicators of labor productivity, for example, the ratio of compliance with norms. To solve the problem of optimal placement in the work mathematical models are built that can take into account various regulatory restrictions and are simple for further software implementation. It is proposed to choose the theory of φ-functions as a basis, which can be characterized as measures of proximity of objects. Thus, the set task of optimal placement of workplaces is reduced to the task of mathematical programming. The objective function determines the criterion of optimality – the minimization of the area or perimeter that will be occupied by the objects. This formulation of the problem is relevant because the use of the smallest production area, taking into account safety requirements, is an economic condition for effective production management. The constraint on the relative location of workplaces is set using φ-functions, which defines the decision domain. That, when formalizing restrictions, you can take into account all regulatory safety distances between workplaces, equipment, walls, etc. Thus, the work explores an approach that will allow automatic planning of the placement of a large number of technological objects, workplaces in accordance with occupational safety standards. Use of the software application, which can be implemented on the basis of the φ-functions apparatus, will significantly reduce the time of workplaces planning and increase its efficiency.

PL

. W strukturze ochrony pracy ważną rolę odgrywa optymalna organizacja miejsc pracy. Projektowanie przestrzeni roboczej powinno zapewnić optymalny podział funkcji pomiędzy człowieka i maszynę w celu stworzenia bezpiecznych warunków pracy, zmniejszenia uciążliwości pracy i poziomu urazów odniesionych w pracy. Najczęściej planowanie miejsca pracy odbywa się ręcznie, poprzez proste obliczenia, a następnie ocenia się racjonalność planowania miejsca pracy na podstawie statystyk urazów i chorób zawodowych, a także wskaźników wydajności pracy, na przykład współczynnika zgodności z normami. Do rozwiązania problemu optymalnego rozmieszczenia budowane są modele matematyczne, które mogą uwzględniać różne ograniczenia normatywne i są proste do dalszej implementacji programowej. Proponuje się wybór teorii funkcji φ, którą można scharakteryzować jako miarę bliskości obiektów. W ten sposób problem optymalnego rozmieszczenia miejsc pracy sprowadza się do problemu programowania matematycznego. Funkcja celu określa kryterium optymalności – minimalizację obszaru lub obwodu, który ma być zajęty przez obiekty. Takie postawienie problemu jest istotne, ponieważ wykorzystanie najmniejszej powierzchni produkcyjnej, z uwzględnieniem wymogów bezpieczeństwa, jest ekonomicznym warunkiem efektywnego zarządzania produkcją. Ograniczenia wzajemnej lokalizacji miejsc pracy ustalane są za pomocą funkcji φ, co określa domenę decyzyjną. Tak więc przy formalizowaniu ograniczeń można uwzględnić wszystkie normatywne odległości bezpieczeństwa między miejscami pracy, urządzeniami, ścianami itp. W związku z tym w artykule badane jest podejście, które będzie automatycznie planować rozmieszczenie dużej liczby obiektów technologicznych, miejsc pracy odpowiednio do standardów bezpieczeństwa pracy. Zastosowanie oprogramowania, które może być realizowane na bazie funkcji φ, znacznie skróci czas planowania miejsc roboczych i zwiększy jego efektywność.

4

Towards Objectification of Multi-Criteria Assessments: a Comparative Study on MCDA Methods

Bączkiewicz Aleksandra, Wątróbski Jarosław, Kizielewicz Bartłomiej, Sałabun Wojciech

Annals of Computer Science and Information Systems

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2021

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Vol. 25

417--425

EN

Objective evaluation in problems considering many, often conflicting criteria is challenging for the decision-maker. This paper presents an approach based on MCDA methods to objectify evaluations in the camera selection problem. The proposed approach includes three MCDA methods, TOPSIS, VIKOR, COMET, and two criterion weighting techniques. Two ranking similarity coefficients were used to compare the resulting rankings of the alternatives: WS and rw. The performed research confirmed the importance of the appropriate selection of multi-criteria decision-making methods for the solved problem and the relevance of comparative analysis in method selection and construction of objective rankings of alternatives.

5

Interval-Valued Intuitionistic Fuzzy Decision-Making Method using Index Matrices and Application in Outsourcing

Traneva Velichka, Tranev Stoyan, Mavrov Deyan

Annals of Computer Science and Information Systems

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2021

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Vol. 25

251--254

EN

Selecting a suitable outsourcing service provider is a challenging problem that requires discussion among a group of experts. The problems of this type belongs to the area of multicriteria decision-making. Interval-valued intuitionistic fuzzy sets, which are an extension of intuitionistic fuzzy sets, are a capable tool in modeling uncertain problems. In this paper we will formulate an optimal interval-valued intuitionistic fuzzy multicriteria decision-making problem in outsourcing and propose a new approach for the selection of the most appropriate candidates; as well as a software program for its automated solution, based on our previous libraries. As an example of a case study, an application of the algorithm on real data from a refinery is demonstrated.

6

Operations research in open-pit mining

Maksymowicz Marcin

Górnictwo Odkrywkowe

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2020

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R. 61, nr 3

31--38

EN

In striving to maximize profits, maximize safety and to meet environmental requirements, management decisions being made in surface mining industry should always be optimal. Operations research, as a discipline supporting the decision-making processes helps to achieve this. In this paper, basic issues related to operations research in open-pit mining are explained. Significance of the operations research is emphasized, presenting the wide range of its applications in open-pit mining industry.

PL

Dążąc do maksymalizacji zysków, maksymalizacji bezpieczeństwa oraz spełnienia wymagań środowiskowych, decyzje zarządcze podejmowane w górnictwie odkrywkowym powinny być zawsze optymalne. Badania operacyjne - jako dyscyplina wspierająca procesy decyzyjne, pomagają to osiągać. W artykule wyjaśniono podstawowe zagadnienia dotyczące badań operacyjnych w branży górnictwa odkrywkowego oraz podkreślono ich znaczenie, przedstawiając szeroki wachlarz zastosowań.

7

Improving the TSAB algorithm through parallel computing

Rudy Jarosław, Pempera Jaroslaw, Smutnicki Czesław

Archives of Control Sciences

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2020

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Vol. 30, No. 3

411--435

EN

In this paper, a parallel multi-path variant of the well-known TSAB algorithm for the job shop scheduling problem is proposed. Coarse-grained parallelization method is employed, which allows for great scalability of the algorithm with accordance to Gustafon’s law. The resulting P-TSAB algorithm is tested using 162 well-known literature benchmarks. Results indicate that P-TSAB algorithm with a running time of one minute on a modern PC provides solutions comparable to the ones provided by the newest literature approaches to the job shop scheduling problem. Moreover, on average P-TSAB achieves two times smaller percentage relative deviation from the best known solutions than the standard variant of TSAB. The use of parallelization also relieves the user from having to fine-tune the algorithm. The P-TSAB algorithm can thus beused as module in real-life production planning systems or as a local search procedure in other algorithms. It can also provide the upper bound of minimal cycle time for certain problems of cyclic scheduling.

8

Pythagorean Fuzzy Analytical Network Process (ANP) and Its Application to Warehouse Location Selection Problem

Yaman Tutku Tuncalı

Annals of Computer Science and Information Systems

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2020

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Vol. 21

137--140

EN

Although new techniques are added to multi-criteria decision-making (MCDM) techniques every day, fuzzy applications of current and proven methods also take a large place in the literature. The main subject of this study is to propose an extension of Pythagorean fuzzy sets (PFS), which are useful to overcome the uncertainty in multi-criteria decision processes, to the well-known Analytical Network Process (ANP) technique. For this purpose, an empirical application of the proposed method was carried out in defining criteria weights of the warehouse location selection problem in the medical sector.

9

Optimization of the enterprise marketing strategy using the operations research

Pesikov E., Zaikin O., Bakhtadze N.

Zeszyty Naukowe Warszawskiej Wyższej Szkoły Informatyki

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2016

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nr 15

67--77

EN

It is examined an approach to the analytical tools construction of marketing of the enterprise designed to select the optimal assortment, sales volume, market segments and product prices and based on the use of the operations research methods and optimal software systems. Is proposed a model of nonlinear integer programming with variables of continuous and boolean type, which allows to plan production of existing and new products. To analyse the optimization model is proposed using of heuristic algorithm based on iterative increase in products prices and solution of the linear integer programming task by method of Land and Doig at each step of changing prices.

10

Poprawa ekonomiki struktury produkcji na podstawie symulacji zdarzeń dyskretnych

Kaczmar I.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2016

|

z. 92

131--141

PL

W artykule przedstawiono nowe możliwości oprogramowania symulacyjnego i jego zastosowanie do optymalizacji struktury produkcji. W wielu przedsiębiorstwach podstawowe pytanie dotyczy ustalenia, ile należy produkować danego typu wyrobu, aby przy limitowanych ilościach środków produkcji zyski ze sprzedaży były maksymalne. W badaniach operacyjnych podobne problemy rozwiązuje się metodami programowania liniowego. W tej koncepcji do rozwiązania problemu zbudowano model symulacyjny procesu produkcyjnego. Użyto nowej generacji środowiska symulacyjnego 3D FlexSim z wbudowanym modułem optymalizacyjnym OptQuest.

EN

This article presents new opportunities of simulation programs and their application for optimizing the production structure. In many enterprises the fundamental question concerns the determination of the amount of goods to be produced with limited quantities of means of production, so that sales proceeds gain the highest level of profits. In operational researches similar problems are being solved by linear programming methods. In this concept of solution there has been built a simulation model of the production process. In this case there was a new generation of 3D FlexSim simulation environment used with the integrated OptQuest optimization.

11

Application of an inhomogeneous CTMC model for a telephone call center

Burak M.

Studia Informatica

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2016

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Vol. 37, nr 2

15--27

EN

In this paper we consider modeling an inbound telephone call center, where the callers may balk or abandon, with an inhomogeneous continuous time Markov chain model. We further discuss the practical application of the uniformization method and compare it to traditional call center modeling methods based on stationary approximations.

PL

W artykule omawiane jest modelowanie telefonicznego call center za pomocą łańcuchów Markowa z czasem ciągłym. Model uwzględnia możliwość rozłączenia się klienta (opuszczenia kolejki), jeżeli nie może być on obsłużony natychmiast (balking) lub gdy okres oczekiwania przekracza jego cierpliwość (abandonment). Artykuł porównuje praktyczne zastosowanie metody uniformizacji oraz metod przybliżonych, zakładających (chwilową) stacjonarność systemu.

12

Cost optimization of blend preparation with the use of the FlexSim environment

Kaczmar I.

Agricultural Engineering

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2015

|

Vol. 19, No. 4

51--60

EN

This work presents a new approach to solving the problem of optimization of selection of the blend components quantity. The problem of blending refers to provision of the required amounts of nutrients, at minimal cost of purchasing the products needed for production of a compound feed. The problem of diet is essential for humans, animals and agricultural production. In the presented case the linear programming method in the FlexSim environment was applied. Firstly a simulation model was built that shows the technology of preparing the mixture, while maintaining the minimum required amounts of nutrients. Secondly, the optimizer tool was used to determine the structure of the nutrients, so that the cost of purchase was the cheapest. The results are presented in a numerical and graphical form.

PL

W niniejszej pracy przedstawiono nowe podejście do rozwiązania problemu optymalizacji doboru ilości składników mieszanki. Problem mieszania odnosi się do zapewnienia wymaganych ilości składników odżywczych, przy minimalnym nakładzie kosztów zakupu produktów koniecznych do wytworzenia mieszanki paszowej. Problem diety jest istotne dla ludzi, zwierząt oraz w produkcji rolnej. W przedstawionym przypadku użyto metody programowania liniowego w środowisku FlexSim. Początkowo zbudowano model symulacyjny, który pokazuje technologię wytwarzania mieszaniny zachowując minimalne wymagane ilości składników odżywczych. Na następnym etapie narzędzie optymalizatora zostało użyte do określenia struktury substancji odżywczych, tak aby na koszt zakupu surowców niezbędnych do produkcji był najniższy.

13

Routing flow-shop with buffers and ready times - comparison of selected solution algorithms

Józefczyk J., Markowski M., Balgabaeva L.

Management and Production Engineering Review

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2014

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Vol. 5, No. 4

26--35

EN

This article extends the former results concerning the routing flow-shop problem to minimize the makespan on the case with buffers, non-zero ready times and different speeds of machines. The corresponding combinatorial optimization problem is formulated. The exact as well as four heuristic solution algorithms are presented. The branch and bound approach is applied for the former one. The heuristic algorithms employ known constructive idea proposed for the former version of the problem as well as the Tabu Search metaheuristics. Moreover, the improvement procedure is proposed to enhance the quality of both heuristic algorithms. The conducted simulation experiments allow evaluating all algorithms. Firstly, the heuristic algorithms are compared with the exact one for small instances of the problem in terms of the criterion and execution times. Then, for larger instances, the heuristic algorithms are mutually compared. The case study regarding the maintenance of software products, given in the final part of the paper, illustrates the possibility to apply the results for real-world manufacturing systems.

14

Suboptimal fault tolerant control design with the use of discrete optimization

Kowalczuk Z., Oliński K. E.

International Journal of Applied Mathematics and Computer Science

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2008

|

Vol. 18, no 4

561-568

EN

This paper presents a concept of designing fault tolerant control systems with the use of suboptimal methods. We assume that a given (nonlinear) dynamical process is described in a state space. The method consists in searching (at the off-line stage) for a trajectory of operational points of the system state space. The sought trajectory can be constrained by certain conditions, which can express faults or failures already detected. Within this approach, we are able to use the autonomous dynamics of the process in order to minimize a control cost index (a sub-optimality property). The search itself is based on finding a cheapest path in a graph structure, which represents the system’s dynamics described in the state space. Such a cheapest path (if it exists) represents the sought trajectory. Another (on-line) design stage consists in tracking this trajectory by an executive controller.

15

Obszary badań Instytutu Automatyki i Informatyki Stosowanej

Zieliński C., Malinowski K., Tatjewski P., Ogryczak W., Pacut A., Toczyłowski E., Sacha K., Kasprzak W.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

|

2006

|

nr 10

289-292

PL

Przedstawiono w sposób ogólny badania prowadzone w Instytucie Automatyki i Informatyki Stosowanej. Obejmują one zagadnienia związane ze: sterowaniem, symulacją i optymalizacją systemów złożonych, biometrią uczeniem maszynowym, robotyką, rozpoznawaniem obrazów i sygnałów mowy, sterowaniem układów nieliniowych, metodami wytwarzania oprogramowania oraz oceny jego jakości, wspomaganiem decyzji, badaniami operacyjnymi, harmonogramowaniem oraz bazami danych. Przedstawiono zarówno dokonania teoretyczne jak i aplikacyjne w tym zakresie.

EN

The paper presents in generał the research conducted at the Institute of Control and Computation Engineering. This research encompasses: control, simulation and optimization of complex systems, biometrics, machine leaming, robotics, pattern and speech recognition, nonlinear control, methods of software engineering and evaluation of its quality, decision support, operations research, scheduling and data bases. Both the obtained theoretical results and application of those results have been presented.

16

Dijkstra's algorithm revisited: the dynamic programming connexion

Sniedovich M.

Control and Cybernetics

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2006

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Vol. 35, no 3

599-620

EN

Dijkstra's Algorithm is one of the most popular algorithms in computer science. It is also popular in operations research. It is generally viewed and presented as a greedy algorithm. In this paper we attempt to change this perception by providing a dynamic programming perspective on the algorithm. In particular, we are reminded that this famous algorithm is strongly inspired by Bellman's Principle of Optimality and that both conceptually and technically it constitutes a dynamic programming successive approximation procedure par excellence. One of the immediate implications of this perspective is that this popular algorithm can be incorporated in the dynamic programming syllabus and in turn dynamic programming should be (at least) alluded to in a proper exposition/teaching of the algorithm.

17

Worst-case relative regret algorithm for task allocation in complex operation system

Józefczyk J.

Systems Science

|

2005

|

Vol. 31, no 2

57-66

EN

The uncertain version of a task allocation problem in a complex of independent operations is considered. The parameters in models of the operations are assumed to belong to given intervals. The objective is to find a time-optimal robust solution in terms of the worst-case relative regret function. The optimal worst-case relative regret task allocation algorithm is presented. It consists in reducing the problem with uncertain input data to a number of deterministic problems whose solution algorithms are known. Special cases and a simple example for the polynomial models of the operations illustrate the solution algorithm.

18

Multicriterial synthesis of logistic systems through the hierarchy analysis

Al-Salaimeh S., Makadmee Z.

Systems Science

|

2005

|

Vol. 31, no 4

107-115

EN

The existing methods of multicriterial synthesis of logistic systems (LS) have been developed and improved according to the complex of technical and economic indications. Capabilities of procedures of scale evaluation and evaluation of the coordination of expert opinion have been expanded, which increased the efficiency of problem solutions on LS synthesis with the quality and quality criteria.

19

On the application of statistical kernel estimators for the demand-based design of a wireless data transmission system

Kulczycki P., Waglowski J.

Control and Cybernetics

|

2005

|

Vol. 34, no 4

1149-1167

EN

The subject of this paper is the task of designing the LMDS (Local Multipoint Distribution System) wireless broadband data transmission system. The methodology of statistical kernel estimators and fuzzy logic using operations research and mathematical programming is applied to find optimal locations for its basestations. A procedure which allows to obtain such locations on the basis of potential customer distribution and their expected demand, also in the cases of uncertain and non-stationary data, is investigated.