Wyniki wyszukiwania - BazTech

1

Fixed fleet open vehicle routing problem: Mathematical model and a modified ant colony optimization

Yousefikhoshbakht Majid, Didehvar Farzad, Rahmati Farhad, Ahmed Zakir Hussain

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2024

|

Vol. 72, nr 1

art. no. e148253

EN

The fixed fleet heterogeneous open vehicle routing problem (HFFOVRP) is one of the most practical versions of the vehicle routing problem (VRP) defined because the use of rental vehicles reduces the cost of purchasing and routing for shipping companies nowadays. Also, applying a heterogeneous fleet is recommended due to the physical limitations of the streets and efforts to reduce the running costs of these companies. In this paper, a mixed-integer linear programming is proposed for HFFOVRP. Because this problem, like VRP, is related to NP-hard issues, it is not possible to use exact methods to solve real-world problems. Therefore, in this paper, a hybrid algorithm based on the ant colony algorithm called MACO is presented. This algorithm uses only global updating pheromones for a more efficient search of feasible space and considers a minimum value for pheromones on the edges. Also, pheromones of some best solutions obtained so far are updated, based on the quality of the solutions at each iteration, and three local search algorithms are used for the intensification mechanism. This method was tested on several standard instances, and the results were compared with other algorithms. The computational results show that the proposed algorithm performs better than these methods in cost and CPU time. Besides, not only has the algorithm been able to improve the quality of the best-known solutions in nine cases but also the high-quality solutions are obtained for other instances.

2

Performance Evaluation of a Zone-based Three-level Heterogeneous Clustering Protocol for WSNs

Rao Sanapala Shanmukha, Shilpi, Kumar Arvind

Journal of Telecommunications and Information Technology

|

2023

|

nr 3

85--93

EN

This paper proposes a zone-based three-level heterogeneous clustering protocol (ZB-TLHCP) for heterogeneous WSNs. In ZB-TLHCP, the sensor field/region is divided into zones where super, advance, and normal nodes are deployed uniformly and randomly. The performance of the proposed ZB-TLHCP system is compared with that of zonal-stable election protocol (Z-SEP), distributed energy efficient clustering (DEEC), and threshold-based DEEC (TDEEC) protocol by varying the number of super and advance nodes, their energy levels for the fixed sensor field, and the total number of nodes. Matlab simulation results revealed that the proposed ZB-TLHCP solution performed better than Z-SEP, DEEC, and TDEEC protocols, as it increased the instability period, prolonged the network's lifetime, and achieved higher throughput values.

3

Controllability of consensus heterogeneous multi-agent networks over continuous time scale

Athira V. S., Muni Vijayakumar S., Rafeek Kallu Vetty Muhammed, Reddy Gudala Janardhana

Control and Cybernetics

|

2023

|

Vol. 52, No. 2

199--245

EN

The research, presented in this paper, concernes the controllability of a multi-agent network with a directed, unweighted, cooperative, and time-invariant communication topology. The network’s agents follow linear and heterogeneous dynamics, encompassing first-order, second-order, and third-order differential equations over continuous time. Two classes of neighbour-based linear distributed control protocols are considered: the first one utilises average feedback from relative velocities/relative accelerations, and the second one utilises feedback from absolute velocities/absolute accelerations. Under both protocols, the network’s agents achieve consensus in their states asymptotically. We observe that both of the considered dynamical rules exploit the random-walk normalised Laplacian matrix of the network’s graph. By categorising the agents of the network into leaders and followers, with leaders serving as exogenous control inputs, we analyse the controllability of followers within their state space through the influence of leaders. Specifically, matrix-rank conditions are established to evaluate the leader– follower controllability of the network under both control protocols. These matrix-rank conditions are further refined in terms of the system matrices’ eigenvalues and eigenvectors. The inference diagrams presented in this work provide deeper insights into how leader– follower interactions impact the network controllability. The efficacy of the theoretical findings is validated through numerical examples.

4

Influence of heterogeneous nucleation on thermodynamic properties of isotactic polypropylene

Barczewski M., Dobrzyńska-Mizera M., Trzeciak M.

Polish Journal of Chemical Technology

|

2013

|

Vol. 15, nr 4

71-74

EN

In this paper we have investigated the effect of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol sorbitol used in varying amounts (0.01 - 1 wt %) on isotactic polypropylene (iPP) matrix. We have used dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) to study glass transition temperatures and crystallinity as a function of the nucleating agent concentration. Isotactic polypropylene samples showed a strong dependency on amount of α nucleating agent used. An increasing content of sorbitol based nucleating agent led to an increase of crystallization temperature upon cooling from the melt at constant rate and a decrease of the glass transition temperatures.

5

Identifying limits of scalability in distributed, heterogeneous, layer based monitoring concepts like SLAte

Hilbrich M., Muller-Pfefferkorn R.

Computer Science

|

2012

|

Vol. 13 (3)

23-33

EN

In this paper we present the concept of a scalable job centric monitoring infrastructure. The overall performance of this distributed, layer based architecture called SLAte can be increased by installing additional servers to adapt to the demands of the monitored resources and users. Another important aspect is to offer a uniform global view on all data which are stored distributed to provide an easy access for users or visualisation tools. Additionally we discus the impact of these uniform access layer on scalability.

6

Zastosowanie nowych modeli klasy lbet do opisu struktury mikroporowatej węglowego sita molekularnego na podstawie pojedynczych i podwójnych izoterm adsorpcji benzenu

Kwiatkowski M.

Karbo

|

2007

|

Nr 1

11-16

PL

W prezentowanych badaniach nowe modele klasy LBET zostały wykorzystane do identyfikacji doświadczalnych izoterm adsorpcji benzenu na sicie molekularnym MSC 5A. Zastosowane modele klasy LBET bazują na uogólnionej teorii BET nazwanej teorią uniBET, prezentowanej szerzej we wcześniejszych pracach zespołu autora. Otrzymane wyniki pokazują, że modele klasy LBET dają dobry wgląd w proces adsorpcji i strukturę mikroporów oraz mogą być dopasowane do różnych danych adsorpcyjnych w szerokim zakresie ciśnień względnych. W szczególności modele klasy LBET dostarczają półilościowych informacji o strukturze porów, mechanizmie klasteryzacji cząsteczek adsorbatu i rozkładzie energii adsorpcji. Zaproponowane wielowariantowe dopasowywanie formuł LBET i analiza najlepiej dopasowanych izoterm dostarczają wiarygodnych informacji o głównych właściwościach układów adsorpcyjnych i uzupełniających informacji o mechanizmie adsorpcji, umożliwiając dzięki temu bardziej niezawodową ocenę struktury poru. Ponadto modele te są łatwe do wykorzystania w badaniu typowych izoterm adsorpcji.

EN

In the presented research the new LBET class models have been employed to identify empirical adsorption isotherms of benzene on molecular sieve MSC 5A. The used LBET class models are based on the generalized BET theory called uniBET, presented wider in the earlier papers of the author’s team. The obtained results show that the LBET class models give good insight into the adsorption process and structure of micropores and may be well fitted to different adsorption data in a wide relative pressure range. In particularly the LBET class models provide semiquantitative information on pore structure, adsorbate clusterisation mechanisms and surface energy distribution. The proposed multivariant fitting of the LBET formulas and analysis of a number of the best fitted variants provides reliable information on the main energetic properties of adsorption systems and complementary information on adsorption mechanisms, thus enabling for more reliable evaluation of a pore structure and they are easily applicable to examination of typical adsorption isotherms. The presented approach to examination of adsorbents of random porous structure may be viewed as an alternative to classical techniques and to more complicated methods of porous structure description.

7

Numerical study of original mathematical models for adsorption on heterogeneous surfaces of carbonaceous materials

Duda J. T., Kwiatkowski M., Milewska-Duda J.

Polish Journal of Applied Chemistry

|

2004

|

Vol. 48, nr 3-4

93-104

EN

The reported research concerns numerical properties of new original models for heterogeneous adsorption on microporous carbonaceous materials. The models are aimed at drawing information on pore structure and capacity on the basis of adsorption isotherms of small molecule adsorbates. One of the problems was an assessment of identification quality of geometrical and energetic parameters of adsorption system on the basis of adsorption process measurements. The key question is how far the models are able to detect effects of the geometry-induced energetic heterogeneity on the adsorption isotherm.

PL

W pracy przedstawiono badania numeryczne właściwości nowych modeli opisu heterogenicznej adsorpcji na mikroporowatych materiałach węglowych. Modele te dostarczają informacji o strukturze porów i ich pojemności na podstawie izoterm adsorpcji substancji małocząsteczkowych. Jednym z analizowanych problemów jest oszacowanie jakości identyfikacji geometrycznych i energetycznych parametrów układu adsorpcyjnego na podstawie danych pomiarowych procesu adsorpcji. Kluczowym pytaniem jest, w jakim stopniu badane modele są zdolne wykryć wpływ geometrii na energetyczną niejednorodność układu adsorpcyjnego.