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1
Content available Maritime sustainability and the need for global performance indicators in shipping: an empirical investigation based on the shipping KPI standard by BIMCO
Darousos E. E., Mejia M. Q, Panteladis I., Pastra A.
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
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2023
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Vol. 17 No. 4
759--768
EN
This paper aims to cover a gap in maritime literature by analysing the performance of the international fleet through the BIMCO Shipping KPI System databases, and by highlighting the necessity for the adoption of Global Performance Indicators to serve the needs of a sustainable maritime industry. The paper investigates the complex interrelations of the various types of performance in shipping, consisting of 57,622 ships of all commercial types, operated from 26 countries, covering the environmental, health, safety management, HR management, navigational safety, operational, security, and technical performance. Results indicate that countries rank differently with regards to the aggregated performance of their respective shipping companies, signifying different managerial approaches. This paper contributes to the discourse of maritime governance, aiming to be of interest to all maritime stakeholders dealing with marine policies and institutional arrangements for the management and regulation of international shipping.
2
Content available Can smart city planning enhance the sustainable transition of the E.U. capitals? A project and strategy-based smart, sustainable performance analysis in the programming period 2014-2020
Szalmáné-Csete Mária, Baranyi Tímea
Production Engineering Archives
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2023
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Vol. 29, Iss. 4
461-473
EN
Cities across the globe perceive their opportunities for digital transition pathways. This paper presents a project and strategy-based assessment of smart city ambitions in the light of sustainable urban development pathways in the European Union capitals considering the programming period 2014-2020. The purpose of the research is to understand better the smart city trends in Europe and identify any correlation between smart city and sustainability ambitions through the European capitals. The basis of the research was the official project result platforms of European funds with priorities related to smart cities. The collected best practices of transnational smart city projects provide statistics from the previous programming period and draw attention to the developing trends of smart city functions and the activity level of European capitals in the digital transition. Results show that between 2014 and 2020 nearly half of the capitals owned a specific smart city strategic document. Evaluating the smart urban performance of the capitals, it can be stated that most smart solutions were implemented related to mobility and environment in the previous period. Furthermore, it was also considered whether smart city projects could facilitate the shift toward sustainability. Based on the assessment of their planning strategies, a complex image of the European capitals has been revealed in their smart city development concepts; their strategic-level planning can be understood better, which is essential for policymaking in the era of digitalisation, identifying synergies with sustainable urban development ambitions, and monitoring the reached targets at the city level.
3
Content available Assessing telecommunication contractor firms using a hybrid DEA-BWM method
Valizadeh Omid, Ghiyasi Mojtaba
Operations Research and Decisions
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2023
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Vol. 33, No. 4
189--200
EN
Telecommunication companies have an important role in technology development, so evaluating the performance of these companies has been an interest of managers. This article uses a hybrid method using data envelopment analysis (DEA) and the best-worst method (BWM) to measure the performance of communication companies. The hybrid DEA-BWM method is used for the weight determination and performance assessment of 17 telecommunication contractor firms in the Khorsan Razavi province of Iran. We considered four inputs: gross losses, sales cost, legal reserve, and fixed assets. On the other side, three outputs including operation income, operation profit, and retained earnings are considered as outputs. Considering the input-output parameters and using the hybrid method by seven selected criteria, we rank all contractor firms. We found that the BPM firm has the best performance while and GKS firm is found as the firm with the weakest performance. Compared with the classical DEA methods, we found more reliable results with higher discrimination power, using the hybrid DEA-BWM.
4
Content available Equivalent availability index for the performance measurement of haul truck fleets
Kristjanpoller Fredy, Viveros Pablo, Zio Enrico, Pascual Rodrigo, Aranda Oscar
Eksploatacja i Niezawodność
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2020
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Vol. 22, no. 4
583--591
EN
This article presents a model of performance analysis for a truck fleet system in an openpit mine, considering special characteristics of haul fleets. In these systems, the expected availability of each piece of equipment and its operating capacity are the fundamental variables to construct a global fleet performance function. Our analytical algorithm considers heterogeneous fleets with known individual characteristics of transport capacity and failure and repair behavior. The results converge to a new indicator denominated “Equivalent Availability” (EA), which arises from the need to evaluate the capacity of the truck fleet to operate at a lower payload than required using different combinations of equipment to achieve an availability goal. EA is a key indicator to determine the productive capacity of a process, and for selecting equipment and their combinations to achieve production objectives. To exemplify the potentialities of the EA, a case study is implemented in a Chilean copper truck fleet mining process.
5
Content available Energy and environmental performance analysis of grid-connected photovoltaic systems under similar outdoor conditions in the Saharan environment
Deriche Mohammed Amine, Hafaifa Ahmed, Tahri Ali, Mohammedi Kamal, Tahri Fatima
Diagnostyka
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2020
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Vol. 21, No. 2
13--23
EN
The aim of this paper is to present a one-year performance analysis of four grid-connected PV systems installed at Ghardaia city in Algeria’s Sahara. The grid-connected PV systems are based on four different PV module technologies which are: monocrystalline silicon (m-Si), multi-crystalline silicon (mc-Si), cadmium telluride (Cd-Te) and amorphous (a-Si) PV module technologies. The PV systems based on the thin film technologies have their performance ratio better throughout the year when the performance ratio of the mc-Si technology is better in the winter season. The a-Si PV system has its performance ratio about 6.13 % more better than mc-Si and 8.90 % better than m-Si. The AC energy produced with the a-Si PV system is 13.32 % more than what the mc-Si system produces. It was found that the a-Si PV system performs better than the other technologies under the Saharan climate conditions of Ghardaia city. The energy payback time (EPBT) and greenhouse gases (GHG) emissions of the different PV systems were analyzed. The EPBT and GHG emissions per year, vary from a minimum value of 2.8 years to a maximum value of 5.73 years and from 13.24 tons to 32.03 tons of CO2/kWh for CdTe and m-Si respectively. The CdTe PV system performs better in terms of EPBT and GHG emissions compared to the other technologies (m-Si, mc-Si and a-Si) due to its low life cycle energy requirement.
6
Prosta metoda detekcji cykli odstawy urobku samojezdnych ładowarek łyżkowych
Stefaniak Paweł, Skoczylas Artur, Koperska Wioletta
Cuprum : czasopismo naukowo-techniczne górnictwa rud
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2020
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nr 2
33--46
PL
W górnictwie podziemnym rud miedzi transport poziomy urobku realizowany jest za pomocą samojezdnych maszyn załadowczo-odstawczych. Przykładowo, w kopalniach rud miedzi KGHM Polska Miedź S.A., gdzie stosowany jest komorowo-filarowy system eksploatacji złoża, odstawa urobku realizowana jest głównie przy współpracy ładowarek łyżkowych i wozów odstawczych. W przypadku krótszych tras odstawy proces ogranicza się już tylko do ładowarek. Obecnie obserwuje się globalny trend w zakresie rozwoju predykcyjnego utrzymania ruchu maszyn górniczych, nawigacji, jak również optymalizacji produkcji z wykorzystaniem przemysłowego internetu rzeczy (ang. Industrial Internet of Things, IIoT). Rozwój analityki w tym zakresie wymaga niestety pełnego wglądu w przebieg pracy maszyny w wyrobiskach górniczych, zapewniający prowadzenie wielowymiarowych analiz do szerszego zrozumienia kontekstów eksploatacji maszyny. W artykule przedstawiono metodę identyfikacji cykli odstawy, jak również składowych podprocesów, realizowanych w każdym pojedynczym cyklu. Zaproponowany algorytm bazuje na użyciu operacji splotu, w celu detekcji skoków obserwowanych w sygnale ciśnienia z siłownika układu hydraulicznego wychyłu łyżki.
EN
In underground mining of cooper ores, horizontal transport of material is performed using self-propelled machines, especially Load-Haul-Dump machines. For example, in KGHM Polska Miedź S.A. underground mines, where room-and-pillar system is used to deposit exploitation, the haulage process is provided by wheel loaders and haul trucks with suitably adjusted operation configuration. In case of shorter haulage routes, only wheel loaders take part in haulage process. Currently, there is observed a global tendency reliant on develop predictive maintenance as well as navigation or production optimization using Industrial Internet of Things (IIoT). Unfortunately, analytics development in this domain requires full insight into machine’s workflow in mining excavations and multivariate analysis in order widely understanding of machine operating contexts. In this article, a quick method to haulage cycle identification on example of wheel loader has been proposed. Developed algorithm is based on hydraulic pressure signal segmentation which provides to recognize loading operation, haulage and return of machine to mining face after unloading material in dumping point. The method is based on smooth hydraulic pressure signal in order to reduce signal interference but introduce to apply a convolution of smoothed signal with inverted step function. The advantage of the algorithm is its simplicity, high accuracy, robustness and low algorithmic complexity.
7
Content available Wpływ wybranych wskaźników jakości regulacji na parametry sygnału sterującego w układzie z regulatorem PID
Pawliński Maciej J., Plamowski Sebastian, Domański Paweł D.
Pomiary Automatyka Robotyka
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2019
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R. 23, nr 1
31--42
PL
Praca ma na celu zbadanie i porównanie regulatorów PID o parametrach uzyskanych w wyniku optymalizacji wybranych wskaźników jakości pod kątem właściwości generowanych sygnałów sterujących. Punktem wyjścia do analizy są symulacje przeprowadzone w środowisku MATLAB przeprowadzone dla pięciu obiektów (z czterech klas) na sześciu typach wskaźników. Przedstawiono w szczegółach zastosowane metody i wykorzystane algorytmy. W pracy prezentowane są otrzymane w trakcie optymalizacji nastawy regulatorów PID, przebiegi sygnałów procesowych w badanych układach regulacji oraz obliczone parametry sygnałów sterujących, a także sformułowane na podstawie badań obserwacje i wnioski.
EN
The goal of this thesis is to assess and compare PID controllers with parameters determined by minimizing select performance indices paying special attention to the attributes of their output signals. Analysis is based on simulations performed using MATLAB for four controlled processes classes and six types of indicators. The methods and algorithms used have been presented in detail. Thesis presents results of the simulations, optimized PID parameters, plots of process signals in examined control systems, calculated control signal attributes and formulated based on experiments observations and conclusions.
8
Content available Performance Assessment of Steel Moment Connections Retrofitted With Various Reduced Section Patterns
Sivandi-Pour Abbas
Civil and Environmental Engineering Reports
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2019
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Vol. 29, no. 4
1--17
EN
It is of high importance in seismic retrofitting of lateral load-bearing systems to increase the connections performance. The crucial point in the steel frame retrofitting process is to create plastic hinges in these types of frames. The formation of plastic hinges in beams and near columns generates large strains on column flanges as well as welding metal and heated surroundings, which can lead to brittle failure. The connection should be designed in such a way as to allow plastic hinge formation at certain points of the beam. One such method suggested for retrofit connections is to reduce the beam section locally away from the connection zone. There are various patterns available to locally reduce the beam section, such as circular, elliptical, and symmetric/asymmetric. In recent years, different proposals have been presented to design these connections which vary from older instructions. For this study, radiused cuts in the flange and slotted holes in the web of connection beams were selected for retrofitting analysis. Cyclic behavior, energy damping levels, and ductility of these connections were studied and compared before and after the retrofit by using nonlinear dynamic analysis. The results showed that the symmetrical circular hole pattern in the beam flanges demonstrated reliable performance.
9
Content available remote Finite element study on pinning retrofitting technique of masonry walls with opening subjected to in-plane shear load
Shrestha K., Nagae T., Araki Y.
Architecture Civil Engineering Environment
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2011
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Vol. 4, no. 4
81-96
EN
The paper focuses on finite element (FE) modelling of in-plane response of retrofitted masonry walls when subjected to quasi-static in-plane cyclic loading. The retrofit technique involves inserting inclined and horizontal stainless steel bars, already practiced in several historical masonry constructions in Japan. The strength of the pinning technique is ease of construction and it maintains the original appearance of the URM walls. This paper presents a 2D FE model for the retrofitted masonry walls, where continuum elements represent brick units, interface elements represent brick unit/mortar interface, and truss elements represent reinforcing bars. FE model with the proposed simplified equivalent vertical bar model, to represent the inclined inserted reinforcing bars, is validated by comparisons with the experimental results. It was found from the experimental and numerical results that retrofitted specimens showed substantial increment in both strength and ductility and showcased the applicability of the pinning retrofitting technique for historical masonry constructions.
PL
W artykule skoncentrowano się na modelowaniu elementami skończonymi naprawionych ścian murowych poddanych quasi statycznemu, płaskiemu obciążeniu cyklicznemu. Technika naprawy, zastosowana w Japonii w różnych obiektach historycznych o konstrukcji murowej, wymaga wkładania ukośnych i poziomych nierdzewnych prętów stalowych. Zaletą takiej techniki kołkowania jest łatwość wykonania oraz zachowanie niezmienionego wyglądu ścian bez zbrojenia. W artykule przedstawiono dwuwymiarowy model elementów skończonych dla naprawianych ścian murowych, gdzie elementy ciągłe przedstawiają poszczególne cegły, elementy kontaktowe odwzorowują powierzchnię styku cegły i zaprawy, a elementy kratownicowe przedstawiają pręty zbrojenia. Model elementów skończonych z zaproponowanym uproszczeniem zastąpienia prętów ukośnych elementami pionowymi został zweryfikowany przez porównanie z wynikami badań doświadczalnych. Na podstawie wyników badań doświadczalnych i numerycznych stwierdzono, że naprawione elementy wykazują znaczący wzrost wytrzymałości i plastyczności, co potwierdza możliwość stosowania tej metody naprawy w historycznych obiektach o konstrukcji murowej.
10
Content available remote Collision Scenario-based Cognitive Performance Assessment for Marine Officers
Kim H., Kim H. J., Hong S.
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
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2010
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Vol. 4, no. 1
73--77
EN
The overall aim of this paper is to determine a fatigue factor that can be applied to human performance data as a part of a software program that calculates total cognitive performance. This program enables us to establish the levels of cognitive performance in a group of marine pilots in order to test a decision-making task based on radar information. This paper addresses one of the factors that may contribute to the determination of various fatigue factors: the effects of different work patterns on the cognitive performance of a marine pilot.
11
Content available remote A frontier-based neural network for assessing the efficiency of activity units
Curram S. P., Athanassopoulos A. D., Shale E. A.
Foundations of Computing and Decision Sciences
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2009
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Vol. 34, No. 1
23-39
EN
This paper uses neural networks to assess the relative efficiency of activity units. A new formulation is proposed whereby the neural network fit is obtained by minimising one-sided errors which are attributed to technical inefficiency, effectively modelling a frontier. Efficiency ratings are given to rank activity units on a (0, 100] scale. Experiments on artificial data are employed to test the proposed method for its accuracy. These results are also compared with the corresponding efficiency ratings obtained from data envelopment analysis. Factors relevant to methodology selection for implementation are discussed. The empirical results of the paper support the potential role of neural networks as a reliable method of frontier efficiency assessment
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