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Tytuł:
Biologically inspired methods for control of evolutionary algorithms
Autorzy:
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/206262.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
algorytm genetyczny
adaptacja
adaptacyjny algorytm ewolucyjny
genetic algorithms
adaptation
adaptive ewolutionary algorithms
Opis:
In this paper two methods for evolutionary algorithm control are proposed. The first one is a new method of tuning tlie probabilities of genetic operators. It is assumed in the presented approach that every member of the optimized population conducts his own ranking of genetic operators' qualities. This ranking enables computing the probabilities of execution of genetic operators. This set of probabilities is a basis of experience of every individual and according to this basis the individual chooses the operator in every iteration of the algorithm. Due to this experience one can maximize the chances of his offspring to survive. The second part of the paper deals with a self-adapting method of selection of individuals to a subsequent generation. Methods of selection applied in the evolutionary algorithms are usually inspired by nature and prefer solutions where the main role is played by randomness, competition and struggle among individuals. In the case of evolutionary algorithms, where populations of individuals are usually small, this causes a premature convergence to local minima. In order to avoid this drawback I propose to apply an approach based rather on an agricultural technique. Two new methods of object selection are proposed: a histogram selection and a mixed selection. The methods described were tested using examples based on scheduling and TSP.
Źródło:
Control and Cybernetics; 2003, 32, 2; 411-433
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of multistage deterministic, stochastic and fuzzy processes in the fuzzy environment via an evolutionary algorithm
Autorzy:
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/970100.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie rozmyte
adaptacyjny algorytm ewolucyjny
fuzzy control
multistage optimal fuzzy control
adaptive evolutionary algorithm
Opis:
This paper deals with the problem of control of deterministic, stochastic and fuzzy systems with a fixed termination time and fuzzy constraints imposed on controls and states. Constrains imposed on the system are given as membership functions of particular fuzzy sets. Transition functions for controlled systems are given as a matrix of transitions between states for a deterministic object, a matrix of probabilities of transitions for a stochastic object and a matrix of membership functions of transitions for a fuzzy system. An optimal (or sub-optimal) control is obtained using a specialized evolutionary algorithm (EA), which is a development over the previously used methods based on simple genetic algorithm. The specialized EA seems to be a very effective tool for solving such a class of optimization problems, comparing advantageously with the traditional simple genetic algorithm approach and with the previously used solutions like dynamic programming or branch and bound. The specialization of the applied EA is obtained using dedicated problem encoding, the method of ranking of genetic operators and the controlled selection of population members.
Źródło:
Control and Cybernetics; 2005, 34, 2; 525-552
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of dynamic market of energy with local energy clusters
Autorzy:
Stańczak, J.
Radziszewska, W.
Powiązania:
https://bibliotekanauki.pl/articles/206625.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
energy market
energy clusters
AA strategy
Opis:
Clusters of energy are a new mechanism, meant to support development of modern power grids in Poland. In this article, we experimentally check the influence of a hypothetical presence of clusters on energy markets. We present a two level real time power market, where the power first is balanced within a cluster and then an inter-cluster trading is performed, in which the country power grid is a participant in the market. We show that it can be beneficial for all parties to maintain such a schema and that it is also a possible direction for further research.
Źródło:
Control and Cybernetics; 2018, 47, 2; 157-171
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolutionary approach to obtain graph covering by densely connected subgraphs
Autorzy:
Stańczak, J.
Potrzebowski, H.
Sęp, K.
Powiązania:
https://bibliotekanauki.pl/articles/206170.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
graph
clique
graph clustering
evolutionary algorithms
Opis:
This article describes two evolutionary methods for dividing a graph into densely connected structures. The first method deals with the clustering problem, where the element order plays an important role. This formulation is very useful for a wide range of Decision Support System (DSS) applications. The proposed clustering method consists of two stages. The first is the stage of data matrix reorganization, using a specialized evolutionary algorithm. The second stage is the final clustering step and is performed using a simple clustering method (SCM). The second described method deals with a completely new partitioning algorithm, based on the subgraph structure we call α-clique. The α-clique is a generalization of the clique concept with the introduction of parameter α, which imposes for all vertices of the subgraph the minimal percentage (α*100%) of vertices of this subgraph that must be connected with vertices of this α-clique. Traditional clique is an instance of α-clique with α = 1. Application of this parameter makes it possible to control the degree (or strength) of connections among vertices (nodes) of this subgraph structure. The evolutionary approach is proposed as a method that enables finding separate α-cliques that cover the set of graph vertices.
Źródło:
Control and Cybernetics; 2011, 40, 3; 849-875
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The airport gate assignment problem – multi-objective optimization versus evolutionary multi-objective optimization
Autorzy:
Kaliszewski, I.
Miroforidis, J.
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/305661.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
airport gate assignment problem
Evolutionary Multi-objective Optimization
mixed-integer programming
Opis:
In this paper, we approach the Airport Gate Assignment Problem by Multi-objective Optimization as well as Evolutionary Multi-objective Optimization. We solve a bi-criteria formulation of this problem by the commercial mixed-integer programming solver CPLEX and a dedicated Evolutionary Multi-objective Optimization algorithm. To deal with multiple objectives, we apply a methodology that we developed earlier to capture decision-maker preferences in multi-objective environments. We present the results of numerical tests for these two approaches.
Źródło:
Computer Science; 2017, 18 (1); 41-52
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finding structure kernel and shell with predetermined cardinality of kernel set, using evolutionary algorithm
Zastosowanie metod ewolucyjnych do wyznaczania struktur kernel and shell w grafie połączeń
Autorzy:
Mażbic-Kulma, B.
Stańczak, J.
Sęp, K.
Powiązania:
https://bibliotekanauki.pl/articles/343831.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
kernel and shell
klika
sieć logistyczna
algorytm ewolucyjny
clique
logistic network
evolutionary algorithm
Opis:
The theory of logistic transportation systems deals with models of phenomena connected with movement of goods and persons. The developed model of the transportation system is expected to simulate a real system, but also should help us to solve given transportation tasks. In order to describe transportation system (rail, bus or air), as a routine a connection graph would be used. Vertices of the graph can be train stations, bus stops etc. The edges show direct connections between vertices. Its direct application can be difficult and computational problems can occur while one would try to organize or optimize such a transportation system. Therefore, a method of aggregation of such graph was introduced, using the general kernel and shell structure and its particular instance the α-clique structured graphs of connections. In the present approach, we use a predetermined number of communication hubs with the possibility of direct determining which nodes should become hubs or selecting them by the solving method. This structure allows to concentrate and order the transport of goods/persons among vertices and enables to reduce the number of analyzed vertices as well as arcs/edges of the graph. To obtain the desired structure, an evolutionary algorithm (EA) was applied.
Teoria logistycznych systemów transportowych zajmuje się zagadnieniem połączeń w przewozach ludzi i towarów. Od modelu systemu transportowego oczekuje się symulowania rzeczywistego systemu w celu rozwiązywania problemów transportowych. Do opisania systemów transportowych (kolejowych, drogowych czy lotniczych) przydatne mogą się okazać grafy. Wierzchołki grafu mogą odpowiadać węzłom logistycznym, takim jak: stacje kolejowe, przystanki autobusowe, lotniska itd., a krawędzie - bezpośrednim połączeniom pomiędzy węzłami. Dokładny model trudno byłoby analizować lub optymalizować, dlatego jako przydatny model proponujemy strukturę kernel and shell oraz jej szczególny przypadek - strukturę α-klikową jako graf odwzorowujący strukturę połączeń. Struktury te umożliwiają koncentrację i zarządzanie transportem pomiędzy węzłami. W celu uzyskania tej struktury stosujemy specjalizowany algorytm ewolucyjny (EA).
Źródło:
Total Logistic Management; 2010, 3; 53-64
1689-5959
Pojawia się w:
Total Logistic Management
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostyka ludzkiej anaplazmozy granulocytarnej
Autorzy:
Grzeszczuk, A.
Stańczak, J.
Pogorzelska, J.
Prokopowicz, D.
Powiązania:
https://bibliotekanauki.pl/articles/2146374.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
anaplazmoza granulocytarna
choroby czlowieka
parazytologia
diagnostyka
Opis:
Diagnostics of human granulocytic anaplasmosis. Human granulocytic anaplasmosis is one of recently emerging tick-borne diseases. The paper summarizes current opinions on diagnostics of this zoonosis, including the recent recommendations of ESCAR (European Society of Clinical Microbiology and Infectious Diseases Study Group on Coxiella, Anaplasma, Rickettsia and Bartonella).
Źródło:
Wiadomości Parazytologiczne; 2005, 51, 2; 109-114
0043-5163
Pojawia się w:
Wiadomości Parazytologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyzwania naukowe informatyzacji uczelni publicznej
Research challenges of public universities computerisation
Autorzy:
Zawiła-Niedźwiecki, J.
Kamińska, A.
Stańczak, J.
Zajkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/108816.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
uczelnia publiczna
strategia informatyzacji
polityka informacyjna
zarządzanie projektami
public university
informatization strategy
information policy
project management
Opis:
Uczelnia publiczna jest podmiotem o szczególnej roli społecznej, funkcjonuje równocześnie w kontekście wielowiekowej tradycji akademickiej i uniwersyteckiej, jaki w ramach bieżących uwarunkowań podmiotów publicznych oraz na konkurencyjnych rynkach edukacyjnym, naukowym i doradczym. Powoduje to potrzebę poszukiwania modelu organizacyjno-funkcjonalnego odpowiedniego dla specyficznej korporacji, jaką jest taka uczelnia. Jest to nie tylko wyzwanie z zakresu praktyki zarządzania, ale i naukowe, dotyczące poszczególnych aspektów funkcjonowania organizacyjnego i zarządzania (Woźnicki, 2007). Celem artykułu jest przedstawienie koncepcji metodycznego podejścia do procesu informatyzacji uczelni publicznej oraz badań, które temu służą. Podjęto tylko te z tych wyzwań, które są związane z prowadzeniem polityki informacyjnej oraz systematyczną informatyzacją uczelni publicznej. Nie wyczerpuje to potencjału wyzwań naukowych nowego organizowania uczelni publicznych w Polsce i zarządzania nimi.
The public university is a entity of a particular social role, functioning simultaneously in the context of the centuries-old tradition of academic and university, as well as under the current conditions of public entities and competitive markets, educational, scientific and advisory capacity. This results in the need to find a model of organizational and functional suitable for a specific corporation which is the university. This is not only a challenge in the field of management practices, but research concerning various aspects of the organization and management. The article only ones with these challenges, which are related to the conduct of information policy and systematic computerization of public university. However, this does not close the potential of the scientific challenges of the new organization and management of public universities in Poland.
Źródło:
Studia Informatica Pomerania; 2016, 42, 4; 97-108
2451-0424
2300-410X
Pojawia się w:
Studia Informatica Pomerania
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identifying main center access hubs in a city using capacity and time criteria. The evolutionary approach
Autorzy:
Owsiński, J. W.
Stańczak, J.
Barski, A.
Sęp, K.
Powiązania:
https://bibliotekanauki.pl/articles/205927.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
transport
urban transport system
Hub and Spoke
Park and Ride
evolutionary algorithm
Opis:
In this paper we consider the well known Hub and Spoke problem, analyzed in the context of Warsaw Public Transport System. Our method was designed for data preprocessing so as to allow using a timetable obtained from the public transport web site after conversion into the required data format. A dedicated evolutionary algorithm method that detects the hubs of almost all available transport means was also developed. The hubs identified are well connected to the center of the city and to other identified hubs (characterized by high capacity or short travel time). These hubs may become the skeleton of the public transport system and, in particular, good points for locating Park and Ride facilities.
Źródło:
Control and Cybernetics; 2016, 45, 2; 207-223
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Występowanie specyficznych przeciwciał anty-Toxoplasma gondii w grupie pracowników leśnych z województwa pomorskiego i warmińsko-mazurskiego
Occurrence of Toxoplasma gondii specific antibodies in group of forestry workers from Pomorskie and Warmińsko-Mazurskie provinces
Autorzy:
Holec-Gąsior, L.
Stańczak, J.
Myjak, P.
Kur, J.
Powiązania:
https://bibliotekanauki.pl/articles/2143790.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
woj.warminsko-mazurskie
toksoplazmoza
wystepowanie
choroby pasozytnicze
pracownicy lesni
parazytologia lekarska
woj.pomorskie
przeciwciala anty-Toxoplasma gongii
Opis:
Toxoplasma gondii infection is one of the most common human zoonosis. Humans acquire toxoplasmosis by consuming raw or undercooked meat, from environments and from via vertical transmission to the foetus through the placenta during pregnancy. In the present study, a total of 784 persons (forestry workers), from north−eastern region of Poland (pomorskie and warmińsko−mazurskie provinces), were tested by using commercially available ELISA test (DiaSorin) to determine the frequency of Toxoplasma gondii infection. The study was based on detection of IgG and IgM specific antibodies in collected serum samples. The T. gondii−specific IgG were found in 490 samples (62.5%), while the IgM antibodies were noted only in 18 persons (3.7%). High prevalence of seropositive results in forestry workers may suggest an occupational exposure of this group to T. gondii.
Źródło:
Wiadomości Parazytologiczne; 2008, 54, 3; 231-236
0043-5163
Pojawia się w:
Wiadomości Parazytologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolutionary approach for obtaining the hub and spoke structure in the logistic network
Autorzy:
Mażbic-Kulma, B.
Stańczak, J.
Owsiński, J. W.
Sęp, K.
Powiązania:
https://bibliotekanauki.pl/articles/343812.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
kernel and shell
hub and spoke
logistic network
evolutionary algorithm
Opis:
In order to describe transportation system, as a routine a connection graph would be used. Vertices of the graph can be train stations, bus stop, airports etc. The edges show direct connections between vertices. A direct application of such graph can be difficult and computational problems can occur while one would try to organize or optimize such a transportation system. Therefore, a method of aggregation of such graph was introduced, using the general kernel and shell structure and a hub and spoke transformation method of the source graph. These structures allow to concentrate and order the transport of goods/persons among vertices and enable to reduce the number of analyzed vertices as well as edges of the graph. In the presented paper we continue our work on kernel and shell and its instance hub and spoke methods of connection graph transformation. In this paper we develop model of the transportation system using the hub and spoke method with predetermined, minimum and indirectly described numbers of hub nodes. To obtain the desired structures, several versions of specialized evolutionary algorithm (EA) were developed and applied.
Źródło:
Total Logistic Management; 2011, 4; 89-105
1689-5959
Pojawia się w:
Total Logistic Management
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Występowanie Cryptosporidium spp. u muchówek synantropijnych na wybranych stanowiskach miejskich i wiejskich
The occurrence of Cryptosporidium spp. in synanthropic flies in urban and rural environments
Autorzy:
Racewicz, M.
Kruminis-Łozowska, W.
Gabre, R.M.
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/2143583.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
srodowisko miejskie
muchowki
Diptera
scierwicowate
srodowisko wiejskie
Sacrophagidae
Cryptosporidium
muchowate
plujkowate
Muscidae
Calliphoridae
pasozyty jelitowe
wystepowanie
pierwotniaki
zwierzeta synantropijne
przenoszenie pasozytow
Opis:
This study was carried out to determine the role of non-biting synanthropic flies as carriers of Cryptosporidium spp. oocysts in the vicinity of the city of Gdańsk (NE Poland). In 2001–2003, flies were collected from three breeding sites: cow sheds and meadows in the Bystra cattle farm and municipal landfill Szadółki using inhaustors (aspirators) and entomologic nets. A total of 2358 specimens of the families: Muscidae (n=1598), Calliphoridae (n=739) and Sarcophagidae (n=21) were collected and analysed in 249 pools consisted of 9.5 insects, in average. Microscopic examination was used to detect Cryptosporidium spp. oocysts in the fly faeces deposited on the glass microscope slides and stained by Zhiel-Nielsen method. The mean number of faecal droplets per one glass slide was 11.5. Ooocysts of Cryptosporidium spp., stained from light pink to bright red, were found in fly faeces deposited on 25 (27.5%) of 91 glass slides checked. The highest prevalence of the pathogen was observed in faecal droplets deposited by flies collected in municipal landfill (50% investigated slides). DNA of Cryptosporidium spp. was extracted from the surface eluants of flies and/or their gut homogenates and purified. Then extracts were examined by PCR using CPB-DIAGF and CPB-DIAGR primers amplifying a variable region SSU-rRNA of all Cryptosporidium species. Altogether 387 isolates, 228 from surfaces and 159 from gut homogenates, were obtained from 249 pools of flies and analyzed. A specific 435 bp fragment of DNA was obtained in 49 (12.7%) lysates tested. In 10.4% pools, DNA of the pathogen was detected only in the surface eluants while in 7.6% only in gut extracts. In the case of two pooled samples (0.8%) Cryptosporidium spp. was found in both types of lysates. In total, Cryptosporidium spp. was detected in 47/249 pools of flies (18.9%). Assumed that each positive pool contained just one infected fly, the percentage of specimens able to oocysts transmission were calculated at the minimal level 2.0% (n=47/2358). The result obtained comfirm that synanthropic flies can harbour oocysts of Cryptosporidium spp. both externally and internally, and disseminate them mechanically in the environment. Therefore, under unsanitary conditions could be involved in the transmission of human and animal cryptosporidiosis.
Źródło:
Wiadomości Parazytologiczne; 2009, 55, 3; 231-236
0043-5163
Pojawia się w:
Wiadomości Parazytologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania nad występowaniem wirusa gorączki Zachodniego Nilu u komarów [Diptera: Culicidae] na wybranych terenach Polski
A study on the occurrence of West Nile virus in mosquitoes [Diptera: Culicidae] on the selected areas in Poland
Autorzy:
Kubica-Biernat, B.
Kruminis-Łozowska, W.
Stańczak, J.
Cieniuch, S.
Powiązania:
https://bibliotekanauki.pl/articles/2143584.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
wirus Zachodniego Nilu
badania terenowe
wystepowanie
choroby wirusowe
goraczka Zachodniego Nilu
Diptera
Polska
Culicidae
komary
Opis:
West Nile virus (WNV), the etiologic agent of West Nile Fever (WNF), an emerging infectious disease that lately has been rapidly extending its range of occurrence from Africa to Middle East, and to Asia and Southern Europe. In Europe, cases of isolating WNV from mosquitoes representing four genera have been reported from Romania, Portugal, France, southern Russia and what is the most important, from Poland’s neighbouring countries as the Czech Republic, Slovakia and southern Ukraine. These data, as well as human and equine cases in the Czech Republic and Belarus, support hypothesis that WNV has already been present also in Poland, the more so, specific antibodies were detected in the sera of birds collected at the Kampinos and Bialowieza Primeval Forests and in human from the vicinity of Bialystok. Mosquitoes were collected in 2004–2009 at indoor and outdoor collection sites in districts: Kujawsko-Pomorskie, Mazowieckie, Podlaskie and Warmińsko-Mazurskie. In total 15400 female mosquitoes were collected in the cow sheds and overwintering in the cellars, and from human bait and CO2 traps. Mosquitoes were sorted by the collecting site, species and sex, and placed in pools of not in more than 50 specimens in special mixture of phenol and chaotropic salts and frozen in –20°C. Altogether, 15400 females were examined. Total RNA were extracted according to protocol of A&A Biotechnology. RT reaction was performed with random primers and 217-nucleotide fragment from the NS5 coding sequence was amplified by heminested PCR. PCR products were analysed on 1.5% agarose gel. The predominant species was Culex pipiens, accounting for over 42% of total insects collection. All obtained results were negative. Further investigations are needed.
Źródło:
Wiadomości Parazytologiczne; 2009, 55, 3; 259-263
0043-5163
Pojawia się w:
Wiadomości Parazytologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The kernel and shell structure as a tool for improving the graph of transportation connections
Autorzy:
Mażbic-Kulma, B.
Owsiński, J. W.
Sęp, K.
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/406561.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
transport
connections graph
hub and spoke
kernel and shell
α-clique
genetic algorithm
Opis:
A model of a transportation system is expected to be useful in simulations of a real system to solve given transportation tasks. A connection graph is routinely used to describe a transportation system. Vertices can be train stations, bus stops, airports etc. The edges show direct connections between vertices. A direct approach can be difficult and computational problems can arise in attempts to organize or optimize such a transportation system. Therefore, a method for aggregating such graphs was introduced, using a general kernel and shell structure and its particular instances: α-clique structured graphs of connections and a hub and spoke transformation of the source graph. These structures enable the concentration and ordering of transport between vertices and reduction of the analyzed graph. To obtain the desired structures, several versions of a specialized evolutionary algorithm were developed and applied.
Źródło:
Operations Research and Decisions; 2013, 23, 2; 91-105
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of an α-clique approach to obtaining the hub and spoke structure in optimization of transportation systems
Autorzy:
Mazbic-Kulma, B.
Owsinski, J. W.
Barski, A.
Sęp, K.
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/205710.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
transport
transport systems
graphs
hub and spoke
evolutionary algorithm
time-wise profitability
Opis:
The paper is devoted to the analysis of a graph transformation, pertinent for the transport and logistic systems and their planning and management. Namely, we consider, for a given graph, representing some existing transport or logistic system, its transformation to a (non-equivalent) so-called ”hub-and-spoke” structure, known from both literature and practice of transportation and logistics. This structure is supposed to bring benefits in terms of functioning and economic performance of the respective systems. The transformation into the ”hub-and-spoke” is not only non-equivalent (regarding the original graph of the system), but is also, in general, non unique. The structure sought is composed of two kinds of elements - nodes of the graph (stations, airports, havens, etc.), namely: the subgraph of hubs, which, in principle, ought to constitute a complete sub-graph (a clique), and the ”spokes”, i.e. the subsets of nodes, each of which is connected in the ultimate structure only with one of the hubs. The paper proposes a relaxation of the hub-and-spoke structure by allowing the hub subgraph not to be complete, but at least connected, with a definite ”degree of completeness” (alpha), from where the name of ”alpha-clique”. It is shown how such structures can be obtained and what are the resulting benefits for various assumptions, regarding such structures. The benefits are measured here with travel times. The desired structures are sought with an evolutionary algorithm. It is shown on an academic example how the results vary and how the conclusions, relevant for practical purposes, can be drawn from such analyses, done with the methods here presented.
Źródło:
Control and Cybernetics; 2018, 47, 2; 173-189
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

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