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Wyszukujesz frazę "maritime research" wg kryterium: Wszystkie pola


Tytuł:
Research on the maritime communication cryptographic chip’s compiler optimization
Autorzy:
Li, S.
Dai, Z. B.
Powiązania:
https://bibliotekanauki.pl/articles/259239.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
maritime communication encryption system
cryptographic SOC
compiler frontend
loop unrolling
Opis:
In the process of ocean development, the technology for maritime communication system is a hot research field, of which information security is vital for the normal operation of the whole system, and that is also one of the difficulties in the research of maritime communication system. In this paper, a kind of maritime communication cryptographic SOC(system on chip) is introduced, and its compiler framework is put forward through analysis of working mode and problems faced by compiler front end. Then, a loop unrolling factor calculating algorithm based on queue theory, named UFBOQ (unrolling factor based on queue), is proposed to make parallel optimization in the compiler frontend with consideration of the instruction memory capacity limit. Finally, the scalar replacement method is used to optimize unrolled code to solve the memory access latency on the parallel computing efficiency, for continuous data storage characteristics of cryptographic algorithm. The UFBOQ algorithm and scalar replacement prove effective and appropriate, of which the effect achieves the linear speedup.
Źródło:
Polish Maritime Research; 2017, S 2; 50-65
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the maritime logistics pricing model of risk-averse retailer-dominated dual-channel supply chain
Autorzy:
Fang, Q.
Tong, Z.
Ren, L.
Liu, A.
Powiązania:
https://bibliotekanauki.pl/articles/258648.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
dual channel
risk-averse
retailer-dominated
supply chain
Opis:
Price decision is studied in a risk-averse retailer-dominated dual-channel supply chain, which consisting of one manufacturers and one retailer with both off-line and on-line channels. Firstly, two mean-variance models in centralized and decentralized supply chain are established. Secondly, the optimal solutions under the two decision modes are compared and analyzed. The results shows that the price of dual-channel of retailer decreased with the increase of retailers’ risk- aversion coefficient and the standard deviation of the fluctuation of market demand, while the wholesale price changes is on the contrary; in addition, when the market demand is greater than a certain value, the prices of dual channel are correspondingly higher in decentralized supply chain than in centralized supply chain, and vice versa. In addition, when the retailer’s risk aversion is in a certain interval, the expected utility of the whole supply chain is greater in centralized supply chain than in decentralized decision, and vice versa. Finally, a numerical example is given to verify the above conclusions.
Źródło:
Polish Maritime Research; 2018, S 2; 107-116
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD optimisation of the longitudinal volume distribution of a ship’s hull by constrained transformation of the sectional area curve
Autorzy:
Kraskowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/32906720.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
parametric optimisation
CFD
model tests
resistance
wave pattern
Opis:
The paper presents a proposal for a formalised approach to hull shape optimisation with respect to total resistance, by fine-tuning longitudinal volume distribution. An algorithm for automated modification of the hull is presented, allowing for varying the sectional area distribution with a negligible influence on the resulting displacement. Computational fluid dynamics (CFD) solver STAR-CCM+ and computer computer-aided design (CAD) software NX were used to search the optimal volume distribution of selected parent shapes, with respect to total resistance. The bow part and the aft part were optimised separately. The resulting resistances of the selected optimal shapes were then verified by means of scale model tests, realised in the towing tank at the Maritime Advanced Research Centre (CTO) S.A. A noticeable gain in total resistance was achieved and confirmed by experimental tests. The proposed approach seems to be a promising method for relatively quick parametric optimisation of the designed hull shapes; it is also applicable for generic CFD optimisation studies.
Źródło:
Polish Maritime Research; 2022, 3; 11-20
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Future sustainable maritime sector: fishing carriers and their adoption to the environmental regulations. Part I
Autorzy:
Yalama, Viktor
Yakovleva, Olga
Trandafilov, Volodymyr
Khmelniuk, Mykhailo
Powiązania:
https://bibliotekanauki.pl/articles/32912854.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
maritime sustainable scenario policy
energy management
energy efficiency
fishing carrier
marine plastic debris
Opis:
The study explored the legislative database for the maritime sector to be sustainable and have an intact blue economy. The problem for organizations with shipowners that have fishing boats older than 20 years is stated. Decision-making authorities face challenges nowadays. To be in the fleet for the next decade, shipowners for their ships should deploy energy efficiency projects for marine system retrofitting to improve energy efficiency and meet environmental regulations. The Ship Energy Efficiency Management Plan’s development principles are discussed due to the current need for its deployment from 2021, so shipowners can contribute to the fast adoption of new regulations by the International Maritime Organization. In this work it is being offered to incorporate energy management issues with guidelines for upcoming regulations as well as those that are currently enforced. To improve energy efficiency, reduce environmental impact and cut fuel consumption costs, marine system retrofitting has been proposed. In this paper the focus is being put on studying energy management strengths and weaknesses which can lead to a qualitative understanding of the performance of the organizational structure, this work also focuses on the management settings concerning energy efficiency. If the organization wants to win by integrating energy policy, high-quality communication or promotion of energy efficiency issues should be employed. Marine plastic debris challenges fishing carriers on the African Union route. A possible beneficial solution for shipowners is discussed in this study.
Źródło:
Polish Maritime Research; 2022, 3; 69-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of weld deformations by numerical methods - review
Autorzy:
Kozak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/32887011.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
welding distortion
shipbuilding welding
numerical simulation
Opis:
The welding process is the basic technique of joining in the shipbuilding industry. This method generates welding distortions that cause a lot of problems during the manufacturing process due to both the time and cost of straightening as well as their influence on later stages of production. Proper preparation of welding processes plays a growing role in the shipbuilding industry and the development of calculating tools is being observed. The paper presents a review and critical analysis of numerical methods for the assessment of welding distortion.
Źródło:
Polish Maritime Research; 2022, 1; 97-107
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding fuel saving and clean fuel strategies towards green maritime
Autorzy:
Van Nhanh, Nguyen
Rudzki, Krzysztof
Dzida, Marek
Pham, Nguyen Dang Khoa
Pham, Minh Tuan
Nguyen, Phuoc Quy Phong
Nguyen, Xuan Phuong
Powiązania:
https://bibliotekanauki.pl/articles/32919438.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine engine
alternative fuel
green maritime
fuel savings
low-carbon strategy
Opis:
Due to recent emission-associated regulations imposed on marine fuel, ship owners have been forced to seek alternate fuels, in order to meet the new limits. The aim of achieving low-carbon shipping by the year 2050, has meant that alternative marine fuels, as well as various technological and operational initiatives, need to be taken into account. This article evaluates and examines recent clean fuels and novel clean technologies for vessels. The alternative fuels are classified as low-carbon fuels, carbon-free fuels, and carbon neutral fuels, based on their properties. Fuel properties, the status of technological development, and existing challenges are also summarised in this paper. Furthermore, researchers have also investigated energy-saving devices and discovered that zero-carbon and virtually zero-carbon clean fuels, together with clean production, might play an important part in shipping, despite the commercial impracticability of existing costs and infrastructure. More interestingly, the transition to marine fuel is known to be a lengthy process; thus, early consensus-building, as well as action-adoption, in the maritime community is critical for meeting the expectations and aims of sustainable marine transportation.
Źródło:
Polish Maritime Research; 2023, 2; 146-164
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on preventive maintenance strategies and systems for in-service ship equipment
Autorzy:
Song, Tingxin
Tan, Taiyang
Han, Guochen
Powiązania:
https://bibliotekanauki.pl/articles/32887248.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
preventive maintenance
FMEA
lifetime prediction
decision system
ship equipment
Opis:
With continuous improvements in the function and performance of ship equipment, mechanisms of failure have become more and more complicated. To avoid over-maintenance or under-maintenance in existing routine ship maintenance strategies, a ship-level method for repair decisions based on the preventive maintenance concept is proposed in this paper. First, the anticipated repair demand levels of key components are calculated using an improved failure mode and effects analysis (FMEA) method; second, a Weibull distribution model is established, and the parameters are estimated using the maximum likelihood estimation (MLE) to predict the characteristic life of the equipment; then, logical decision principles and rule-based reasoning (RBR) are used to determine the ship repair level and repair timing. Finally, the feasibility and application value of the proposed repair strategy were verified by case studies, and a ship-level system for repair decisions was established.
Źródło:
Polish Maritime Research; 2022, 1; 85-96
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the use of M2M-type NB-IoT and LTE technologies for maritime communication systems
Autorzy:
Gajewski, Sławomir
Czapiewska, Agnieszka
Gajewska, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/32917849.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
NB-IoT maritime solutions
NB-IoT coverage at sea
NB-IoT performance
sea propagation loss
CE2R
CE3R
Opis:
The development of IoT (the Internet of Things) wireless transmission opens a new era in communication systems. In the next years, the development and implementation of IoT systems will be very dynamic. It can be seen that the solutions of LTE – NB-IoT (Long Term Evolution – Narrowband IoT) transmission devices are implemented in a wide range of terrestrial solutions, e.g. smart grids. This paper aims to analyse the possibility of the use of NB-IoT technology for maritime communication applications and partially, for some maritime safety solutions, based on signal coverage analysis at sea. An interesting approach is the comparison of the results of NB-IoT coverage to the classic cellular LTEbased communication systems. Proposed solutions are based on the practical implementation of a designed specialised data concentrator with implemented gateway and radio modems, for both NB-IoT technology as well as LTE. In the paper, analyses of radio link budget and propagation loss models for sea environment are presented. The coverage analysis is based on real measurements of the efficiency of transmissions using wireless modems implemented in the developed data concentrator.
Źródło:
Polish Maritime Research; 2023, 1; 126-134
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and operational diagnostics of marine propellers made of polymer materials
Autorzy:
Kluczyk, Marcin
Grządziela, Andrzej
Batur, Tomislav
Powiązania:
https://bibliotekanauki.pl/articles/32898214.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
diagnostics
polymeric materials
propellers
Opis:
There has been a rapidly growing interest in the use of composite and polymer materials for the construction of marine propellers for over 20 years. The main advantages of these materials are a reduction in the weight of the propeller, increased efficiency due to the hydroelasticity effect, a reduction of the hydroacoustic signature, and a cost reduction for serial production. This paper presents an overview of diagnostic methods that can be applied at the design level and during the operation of marine propellers made of polymeric materials. Non-invasive contact and non-contact-based diagnostic techniques for evaluating the technical state of the propeller are reviewed, and the advantages and disadvantages of qualitative and quantitative methods are identified. Operational diagnostic procedures for propellers are areessential for the safety of vessels at sea. Finally, the structure of a diagnostic system is proposed. It combined diagnosis process with the genesis of damage and the prognosis of the technical condition, i.e. production and in-service diagnostics.
Źródło:
Polish Maritime Research; 2022, 4; 115-122
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of model-scale open-water test uncertainty
Autorzy:
Król, Przemysław
Powiązania:
https://bibliotekanauki.pl/articles/32898216.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
uncertainty
propeller open-water test
lifting surface method
model-scale experiment
propulsion
Opis:
Within the frame of CTO’s standard procedure, a propeller open-water test is preceded by a reference measurement, which is taken for a reference propeller model (P356). The results of these measurements are assembled to conduct an open-water test uncertainty analysis. Additional material was gathered from open-water tests that were conducted throughout several research projects on the CP469 model, which is a model of the Nawigator XXI propeller. The latter is a controllable pitch propeller; its pitch was reset before each test repetition. Known procedures for the determination of the open-water test uncertainty do not allow one to extract the manufacture impact directly, without building many models. This factor was addressed with the use of lifting surface calculations. Under certain additional assumptions, these calculations were performed for 100 generic versions of each propeller’s geometry, which were generated by random deviations from the theoretical data within the limits of allowed tolerances. The results of the conducted analyses made it possible to extract separate factors, which were connected to the test’s repeatability, measurement bias and geometry tolerance.
Źródło:
Polish Maritime Research; 2022, 4; 4-11
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of material thickness on the ductile fracture of steel plates for shipbuilding
Autorzy:
Jakub, Kowalski
Janusz, Kozak
Powiązania:
https://bibliotekanauki.pl/articles/32912848.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ductility
toughness
plasticity
CTOD
Opis:
In the shipbuilding industry, the risk of brittle fractures is relatively high because some units operate in arctic or subarctic zones and use high thickness (up to 100 mm) steel plates in their structures. This risk is limited by employing certified materials with a specific impact strength, determined using the Charpy method (for a given design temperature) and by exercising control over the welding processes (technology qualification, production supervision, and non-destructive tests). However, for offshore constructions, such requirements may prove insufficient. For this reason, regulations employed in constructing offshore structures require conducting crack tip opening displacement (CTOD) tests for steel and welded joints with thicknesses exceeding 40 mm for high tensile strength steel and 50 mm for other steel types. Since classification codes do not accept the results of CTOD tests conducted on specimens of sub-sized dimensions, the problem of theoretically modelling the steel construction destruction process is of key importance, as laboratory tests for notched elements of considerable thickness (100 mm and higher) are costly and problems stemming from high loads and a wide range of recorded parameters are not uncommon. The aim of this research is to find a relationship between material thickness and CTOD value, by establishing and verifying a numerical model that allows recalculating a result obtained on a sub-size specimen to a full- size specimen for a ductile fracture mode. This work presents results and conclusions from numerical modelling and compares them with laboratory test results of the elastic-plastic properties of high thickness steel, typically used in offshore applications.
Źródło:
Polish Maritime Research; 2022, 3; 160-166
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consistent design of PID controllers for an autopilot
Autorzy:
Świder, Zbigniew
Trybus, Leszek
Stec, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/32917355.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
course control
autopilot
track control
PID tunings
Opis:
A consistent approach to the development of tuning rules for course-keeping and path-tracking PID controllers for a ship autopilot are presented. The consistency comes from the observation that for each of the controllers the controlled plant can be modelled by an integrator with inertia. In the case of the course controller, it is the well-known Nomoto model. The PID controller may be implemented in series or parallel form, the consequence of which is a 2nd or 3rd order of the system, specified by a double or triple closed-loop time constant. The new tuning rules may be an alternative to the standard ones given in [1,2]. It is shown that, whereas the reference responses for the standard and new rules are almost the same, the new rules provide better suppression of disturbances such as wind, waves or current. The parallel controller is particularly advantageous. The path-tracking PID controller can provide better tracking accuracy than the conventional PI. Simulated path-tracking trajectories generated by a cascade control system are presented. The novelty of this research is in the theory, specifically in the development of new tuning rules for the two PID autopilot controllers that improve disturbance suppression.
Źródło:
Polish Maritime Research; 2023, 1; 78-85
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ophthalmic injuries in sailors and sea workers – pathomechanism and treatment
Autorzy:
Grąbczewski, Andrzej
Jendrzejczyk, Martyna
Klekot, Grzegorz
Skopiński, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/32917890.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ophthalmic injuries
sea workers
Opis:
The purpose of the article is to do a literature review and present own experience regarding the main causes of ophthalmic injuries in sailors and crew workers. Sailors and sea workers often use heavy equipment when working on a vessel, offshore platform or other. Using these types of tools often carries high risk of injury. They are also exposed to various chemicals, many of which are eye irritants. Ophthalmic injuries are common but rarely fatal. They can lead to vision loss, reduce the quality of life and inability to continue work. The categorized types of these injuries and included chemical, mechanical, electrical, diving related barotrauma and infections. We present the most common cause of these types of injury, situations in which they can occur, pathomechamism of eye damage, recommend a prevention method, recommend the possible first aid and present cases in which specialized treatment in a reference hospital is necessary.
Źródło:
Polish Maritime Research; 2023, 1; 156-162
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A generative approach to hull design for a small watercraft
Autorzy:
Karczewski, Artur
Kozak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/32917891.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
method
generative design
yacht
optimisation
genetic algorithm
Opis:
In the field of ocean engineering, the task of spatial hull modelling is one of the most complicated problems in ship design. This study presents a procedure applied as a generative approach to the design problems for the hull geometry of small vessels using elements of concurrent design with multi-criteria optimisation processes. Based upon widely available commercial software, an algorithm for the mathematical formulation of the boundary conditions, the data flow during processing and formulae for the optimisation processes are developed. As an example of the application of this novel approach, the results for the hull design of a sailing yacht are presented.
Źródło:
Polish Maritime Research; 2023, 1; 4-12
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic positioning capability assessment based on optimal thrust allocation
Autorzy:
Piekło, Agnieszka
Witkowska, Anna
Zubowicz, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/34604896.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
optimal thrust allocation
dynamic positioning
quadratic programming
Opis:
The article presents an efficient method of optimal thrust allocation over the actuators in a dynamically positioned ship, according to the DNV-ST-0111 standard, Level 1. The optimisation task is approximated to a convex problem with linear constraints and mathematically formulated as quadratic programming. The case study is being used to illustrate the use of the proposed approach in assessing the DP capability of a rescue ship. The quadratic programmingbased approach applied for dynamic positioning capability assessment allows for fast calculations to qualitatively compare different ship designs. In comparison with the DNV tool, it gives 100% successful validation for a ship with azimuth thrusters and a pessimistic solution for a ship equipped with propellers with rudders. Therefore, it can be safely applied at an early design stage.
Źródło:
Polish Maritime Research; 2023, 2; 28-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł

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