Carrier Operations Research Articles

A Study of the Method for Calculating the Optimal Generator Capacity of a Ship Based on LNG Carrier Operation Data

Currently, the total generator capacity installed in most ships is greater than the required capacity. In addition, due to new environmental regulations, various auxiliary gears are required to avoid breaking the law. Therefore, the internal environments of ships, such as their machine rooms, have become narrower, making creating space more important than ever before. This paper provides a method for optimizing generator capacity through an analysis of total load data in order to avoid overestimating the generator capacity. In addition, an actual situation in which the generator capacity is determined by the number of cylinders is considered. Three practical case studies with different possible combinations of generators and varying capacities are presented. Therefore, this method can secure space and reduce weight, which can be beneficial in many ways. Additionally, since it does not require various types of data, this information can be used for already built ships or those that will be made in the future.

A risk-constrained time-dependent cash-in-transit routing problem in multigraph under uncertainty

The Cash-in-Transit (CIT) deals with the transportation of banknotes, coins, and other valuable items. Due to the high-value density of these products, incorporating security strategies in the carrier operations is crucial. This paper proposes new CIT models involving deterministic and stochastic time-varying traffic congestion. Since risk exposure of a vehicle is proportional to the time-dependent travel time, a new formula is introduced to measure the risk of traveling. Moreover, this study covers one of the important weaknesses of previous CIT routing models by investigating the problem in multigraph networks. Multigraph representation maintains a set of non-dominated parallel arcs, which are differentiated by two attributes including travel time and robbery risk. Considering maximum allowable time duration together with a risk threshold yields to design a more balanced routing scheme. Multi-attribute parallel arcs in a stochastic time-dependent network bring high computational challenges. Herein, we introduce efficient algorithms including a novel flexible restricted Dynamic Programming and a self-adaptive caching Genetic Algorithm. The proposed algorithms are tested on both a real case study in Isfahan metropolis and generated instances. Ultimately, sensitivity analyses are conducted to assess the importance of the use of multigraph networks in the CIT and to provide significant managerial insights for administrators and practitioners.

Lars Celander. 2018. How Carriers Fought: Carrier Operations in WWII

Lars Celander. 2018. How Carriers Fought: Carrier Operations in WWII

Interface Modification in Three‐Terminal Organic Memory and Synaptic Device

AbstractInterface is a valuable research area for the three‐terminal organic memory device, which is an important member of memory family, as the transport and trapping operation of charge carriers are related to the interfaces between semiconductor/dielectric layers and source‐drain electrodes/semiconductor layer. This progress report highlights the developments of the interface effect for three‐terminal organic memory devices. First, the goals of the interface modification, mainly to adjust the morphology, enhance the adhesion between two layers, change the surface diploes, and regulate the surface energy, are described since the memory characteristic depends on the interfacial property. Second, two common methods are proposed to improve the performance of devices through interface engineering, including fabricating self‐assembled monolayers (SAMs) and thin films with polymers as the interfacial layer. Third, three‐terminal organic memory devices would also be introduced in interfacial engineering since they can be used to simulate various functions of synapses. In the end of this report, the challenges of the interface modification in three‐terminal organic memory devices are discussed.

Integrated Planning for Multimodal Networks with Disruptions and Customer Service Requirements

Multimodal carriers are third-party logistics providers who utilize multiple modes of transportation to deliver timely door-to-door services to their customers. Notwithstanding frequent service disruptions, customers have ever-increasing expectations for on-time deliveries, posing significant challenges to tactical planning. Inspired by the operations of actual carriers, we study the tactical decision planning of multimodal freight networks, considering operational disruptions, timetabling restrictions, and explicit customer service requirements. Despite our focus on tactical planning, our models integrate long-term commitments by penalizing deviations from strategic goals with last-minute operational planning decisions, which are recourse actions aiming to accommodate service disruptions. After improving the dual bound of our initial formulation, we provide reduced-sized models for the special cases of nonpropagating delays and nonreactive last-minute decisions. This latter formulation is utilized to construct scenario-based and trip-based heuristics, which we combine in a hybrid search loop. Our computational study illustrates that our approach attains high-quality solutions for real-sized instances that are otherwise unsolvable by off-the-shelf optimization software, and a significant improvement over a nontrivial rolling horizon benchmark.

Energy Commitment for a Power System Supplied by Multiple Energy Carriers System using Following Optimization Algorithm

In today’s world, the development and continuation of life require energy. Supplying this energy demand requires careful and scientific planning of the energy provided by a variety of products, such as oil, gas, coal, electricity, etc. A new study on the operation of energy carriers called Energy Commitment (EC) is proposed. The purpose of the EC is to set a pattern for the use of energy carriers to supply energy demand, considering technical and economic constraints. EC is a constrained optimization problem that can be solved by using optimization methods. This study suggests the Following Optimization Algorithm (FOA) to solve the EC problem to achieve technical and economic benefits. Minimizing energy supply costs for the total study period is considered as an objective function. The FOA simulates social relationships among the community members who try to improve their community by following each other. Simulation is carried out on a 10-unit energy system supplied by various types of energy carriers that includes transportation, agriculture, industrial, residential, commercial, and public sectors. The results show that the optimal energy supply for a grid with 0.15447 Millions of Barrels of Oil Equivalent (MBOE) of energy demand costs 9.0922 millions dollar for a 24-h study period. However, if the energy supply is not optimal, the costs of operating energy carriers will increase and move away from the optimal economic situation. The economic distribution of electrical demand between 10 power plants and the amount of production units per hour of the study period is determined. The EC outputs are presented, which include an appropriate pattern of energy carrier utilization, energy demand supply costs, appropriate combination of units, and power plant production. The behavior and process of achieving the answer in the convergence curve for the implementation of FOA on EC indicates the exploration and exploitation capacity of FOA. Based on the simulated results, EC provides more information than Unit Commitment (UC) and analyzes the network more efficiently and deeply.

A bi-level market-clearing for coordinated regional-local multi-carrier systems in presence of energy storage technologies

A multi-energy system (MES) provides greater flexibility for the operation of different energy carriers. It increases the reliability and efficiency of the networks in the presence of renewable energy sources (RESs). Various energy carriers such as power, gas, and heat can be interconnected by energy storage systems (ESSs) and combined heat and power units at different levels (e.g., within a region or a local). Non-coordinated optimization of energy systems at local and regional levels does not verify the whole optimal operation of systems since the systems are operated without considering their interactions with each other. One of the most famous sources of flexibility is ESSs. Hence, this paper presents a stochastic decentralized approach to evaluate the impact of ESSs on regional-local MES market-clearing within a bi-level framework. On the regional level, the economic interaction between the electricity and natural gas (NG) systems is carried out by a centralized system operator (CSO). In addition, coordination between various energy carriers is implemented by the energy hub operator at the local level. To ameliorate the flexibility of the NG system in the regional MES, the linepack model of gas pipelines has been considered. Local MES modeling is performed through multiple input/output ports using a linear energy hub model. The proposed model is a mixed-integer linear programming (MILP), which is solved by CPLEX solver in GAMS software.

Airport efficiency in the dawn of privatization: The case of Greece

Until recently, all airports in Greece were owned and managed by the state; however, the recent economic crisis led the Greek government to privatize 14 regional airports. This paper evaluates the performance of the 38 Greek airports open to civil aviation just before the privatization was concluded. It also aims to highlight that the majority of airports with high efficiency were selected to be privatized. The analysis was performed applying Data Envelopment Analysis (DEA) and Malmquist Productivity Index (MPI) using 2011 and 2015 operational and financial data. Results showed that, despite the economic crisis, overall efficiency improved between 2011 and 2015, mainly due to the spectacular increase in incoming international passenger traffic. Changes in efficiency can be attributed by and large to exogenous factors such as operations of low-cost carriers and charter operators along with the seasonal operations of established carriers at individual airports. Findings confirm that the majority of high efficiency airports were offered to private investors.

Omnichannel logistics network design with integrated customer preference for deliveries and returns

This paper proposes a mixed integer program (MIP) for the network design problem of a parcel carrier that manages online orders from omnichannel retailers. The network includes several types of facilities, such as city distribution centers, intermediary depots, parcel offices, as well as collect channel points, such as automated parcel stations (APS), stores or kiosks. The model formulation takes into account the influence of these collection points on consumer choice and the maximum distance customers are willing to walk to reach them. Realistic transportation costs are also considered, including detailed long haul costs and delivery costs in an area. The transportation costs inside an area are estimated via the Continuous Approximation proposed by Newell (1971) and Newell (1973), which results in a simpler problem than a location-routing problem, however, at the cost of losing linearity. For a special case of the problem, we propose a heuristic that, in our experimental setting, is on average 42.5 faster than the overall MIP and gives solutions within 1.02% of the optimum. Finally, we use the model to discuss the network design of a Spanish parcel carrier operating in Madrid.

Thickness effect on low-power driving of MoS2 transistors in balanced double-gate fields

In field-effect transistors (FETs), when the thickness of the semiconducting transition metal dichalcogenides (TMDs) channel exceeds the maximum depletion depth, the entire region cannot be completely controlled by a single-gate electric field. The layer-to-layer carrier transitions between the van der Waals interacted TMD layers result in the extraordinary anisotropic carrier transport in the in-plane and out-of-plane directions. The performance of the TMD FETs can be largely enhanced by optimizing the thickness of the TMD channel as well as increasing the effective channel area through which the gate field is delivered. In this study, we investigated the carrier behavior and device performance in double-gate FETs fabricated using a 57 nm thick MoS2, which is thicker than the maximum depletion depth of about 50 nm, and a much thinner 4 nm thick MoS2. The results showed that in the thick MoS2, the gate voltages at both ends formed two independent channels which had no synergistic effect on the device performance owing to the inefficient delivery of the vertical electric field. On the other hand, in the thin MoS2 channel, the double-gate voltages effectively controlled one channel, resulting in twice the carrier mobility and operation in a low electric field region, i.e. below 0.2 MV cm−1.

ВПЛИВ ЕВОЛЮЦІЙНИХ ПРОЦЕСІВ НА РОЗВИТОК ІНФРАСТРУКТУРИ ЗАЛІЗНИЧНОГО ТРАНСПОРТУ

The article deals with the stages of railway transport infrastructure component evolutionary development. It is noted that with the loss by the railway industry of its naturalness, as it is a natural monopoly, the status of the infrastructure in it changes. Herewith, as a rule, a new model for managing railway transport is formed. The next stage in the development of infrastructure begins. The author outlines the reasons for the transition from one stage in the evolution of infrastructure to the next.In the process of research, three stages of the evolutionary development of railway transport infrastructure are identified. The first one is when infrastructure acts as a component of monopoly formation. The second one is when an infrastructure company becomes a vertically separated independent entity. The third one is when an infrastructure company becomes a member of a vertically integrated association created through strategic partnerships with carrier operators and the state. It is proved that changing the place of the infrastructural component determines the features of its functioning and the degree of risk. The characteristic features of the infrastructure company at each stage of development are highlighted. The emphasis is placed on the practicability of allowing Ukrainian railway companies to pass the second stage in infrastructure development.It is noted that the functioning of the infrastructure company as a part of a vertically integrated association through the development of strategic partnerships with carrier operators is more acceptable and appropriate. The world experience shows that for railway networks with a high traffic density and a large share of freight trains, the advantage is not the vertical separation and attempts to introduce competition, but the improvement of the state policy in the field of railway transport, motivation and management systems in the industry.

Leadership lessons from the Titanic and Concordia disasters

PurposeThis paper aims to investigate two famous disasters at sea, the Titanic and the Concordia, separated by 100 years, based on a comparison and analysis of those historical events, demonstrating how lessons learned and training methods used in the hazardous marine environments of aircraft carrier operations, as well as the near-solo conditions of technical scuba diving, can be better implemented in managing a large ship at sea.Design/methodology/approachThis study starts with a historical analysis of these two ship-wrecks, both large, technically advanced ships that sank due to poor leadership, a breakdown in command and panic. Next, the study compares and contrasts scuba with operations aboard an aircraft carrier, two different maritime scenarios, yet similar in that there are many hazards that may require split-second decisions with limited or no communication with others. Both these mind-sets and training approaches have direct application to leadership and disaster planning on a large ship by being focused on minimizing decisions under stress in order to reduce panic.FindingsThis study demonstrates the value and impact of training that minimizes decisions under stress and enable people to make decisions independently in the face of a loss of communications. Focusing on two famous naval accidents, our analysis shows how such training can prevent panic and disaster, and can have direct application to leadership and disaster planning on a large ship.Originality/valueThis study uniquely compares and contrasts many of the planning and decision-making strategies used for both aircraft carrier operations and technical scuba diving, and the need to be able to make split-second decisions without communicating to others, and how these approaches can be used to better train a commercial ship to respond to an unforeseen disaster at sea.

Improved self-seeding and carrier remodulation performance for WDM-PON by means of double RSOA erasure

In this work, we investigated a novel wavelength division multiplexing passive optical network (WDM-PON) configuration, based on cascaded reflective semiconductor optical amplifiers (RSOA) data erasure for combined self-seeding and wavelength reuse. Improved performance is achieved by enhanced erasure efficiency using a self-seeded double-RSOA cavity at the optical line terminal (OLT) and cascaded RSOAs at the optical network terminal (ONT). To carry out the study, our experimental results for our earlier combined topology layout operating at a symmetric transmission were used to validate the simulation framework for the proposed double-RSOA erasure configuration. Using our original single-cavity self-seeding WDM-PON architecture as a benchmark, downstream extinction ratio (ERD) margins of 6.5 dB and 9.0 dB are obtained, for generating self-seeded downstream signals and upstream remodulation, respectively. Also, bidirectional transmission of 1.25 Gb/s over links reach up to 45 km is achieved by the double-RSOA cavity, surpassing in 25 km our original combined topology. The results indicated that our proposition effectively addresses a fundamental trade-off for WDM-PONs based on the wavelength reuse and/or self-seeding techniques. Specifically, the double erasure procedure allows the use of relatively high levels of ERD, thereby providing improved bit error rate (BER) at the ONT, while assuring high-quality generation of the self-seeding carrier and loopback operation.

Structural Analysis of Network Connections of Koleje Małopolskie sp. z o.o. as a Significant Element of the Management of the Transport Company

Public transport is one of the most important elements of the economy and social space development in which it is located. Issues related to its proper organisation are very often the responsibility of transport companies, which must operate and carry out their activities within the principles of the economy, that is, the principles of managing a service company. An important element of an efficient and effective functioning of a transport company is the quality of the provided services. An element significantly affecting the quality of the services offered is, inter alia, an appropriately organised network of connections offered by the carrier. This network in an efficient and interference-resistant manner must facilitate transport in a given area. In the article, using the graph theory and the simulation method, the structure of network connections of a railway carrier operating in the Małopolska region (Koleje Małopolskie sp. z o.o.) in Poland was analysed. The aim of the analysis was to obtain information about the current condition and parameters of the network offered by the carrier. Theconducted analysis made it possible to assess the current state as well as within the conducted research and it proposed to modify the existing network of connections in order to improve its parameters. The carrier’s network is used, inter alia, to co-create public transport in the region, and the structure of the connections network and its appropriate planning can have a significant impact on the functioning of the company.

Risky business: Investigating influences on large truck drivers' safety attitudes and intentions

Introduction: Safety research in the U.S. motor carrier context remains important, as the trucking industry employs approximately 1.7 million large truck drivers. Drivers face many competing pressures in this unique high risk, high regulation, and low direct supervision context. They represent the cornerstone of safe carrier operations. Methods: Using a multi-theoretical approach, this study investigates how drivers' perceptions of carrier safety climate influence their safety-related attitudes and intentions. Results: Responses from nearly 1500 over the road drivers provide evidence that safety climate directly influences drivers' attitudes toward safety, safety norms, and driver risk avoidance, and indirectly influences drivers' intentions to commit unsafe acts. These findings replicate previous findings and also extend the nomological network of theory in this context, adding driver risk avoidance as a central factor to the driver safety theoretical framework. Additionally, carrier managers are encouraged to reflect on the study's evidence and pursue a better understanding of their drivers' risk perceptions and tolerance, while minimizing avoidable risk through prudent safety and operational policies, procedures, and processes. Future research in this area is highly encouraged.

Regional Integration in Air Transportation towards a Fully Integrated Sky: A Comparative Case Study between EU and ASEAN

항공운송은 지역경제통합에서 중요한 분야이다. 항공운송에서 지역통합은 항공자유화협정으로 알려진 두 국가 혹은 한 지역 내에서 영공이 개방되는 것으로 귀결된다. 현재 항공자유화가 완결된 유일한 지역은 EU이고, 회원국 간 모든 비준 절차가 완료되었음에도 ASEAN에서 항공자유화의 진행은 EU에 비해서 더디게 이루어지고 있다. 본 연구는 항공자유화 진행에 대한 연구로, 지역통합 이론과 EU사례를 접목하여, ASEAN에서 항공자유화가 성공적이지 못했는가에 대한 이유를 분석하였다. 본 연구는 항공자유화협정이 현재 항공시장에서 중요한 시장점유율을 보이고 있는 저비용항공사(LCC)의 발전과 연관되어 있음을 주목한다. LCC의 성장은 FSC를 위협할 정도가 되었고, FSC는 LCC를 모방하거나 FSC 내에 LCC자회사를 설립하고 있다. 본 연구는 다양한 사례연구를 진행하면서, EU와 ASEAN간의 차이에 주목하였다. 그리고 EU의 사례에 대한 연구분석은ASEAN 항공시장자유화의 진행상황을 진단하는데 유용하였다. 전 세계에서 유일하게 완벽한 항공시장 자유화를 구현한 EU사례연구는 EU와 ASEAN이 여러 관점에서 차이가 있음에서 ASEAN에서 항공자유화가 성공적으로 진행되기 위해서 반드시 고려되어야 한다. EU사례의 활용은 EU가 항공자유화를 발전시키는데 직면했었던 난관을 아세안이 미리 예방을 하거나 최소화하는데 기여할 것이다.Liberalization of aviation market is an important part of economic regional integration. Regional integration in air transportation is associated with the liberalization of the air space between two countries or within a region, as is known as Open Sky Agreement (OSA). The European Union is a fully-liberalized region of aviation market. Meanwhile, even though the member states of ASEAN completed the ratification of all the protocols about the Open Skies, the implementation of OSA in ASEAN is slow. The emphasis of this paper was to look at the relevance of OSA in two regions (EU and ASEAN) and analyzes some of the reasons why ASEAN has not been successful. The important finding of this study is that Open Sky Agreement leads to the development of Low-Cost Carriers (LCCs) which now have an essential share in the aviation market. The emergence of LCC threatens the operation of Full Services Carriers which nowadays tend to imitate the strategy of LCC or create their own LCC subsidiaries. This comparative cases of EU and ASEAN represent(economic, institutional and strategic) the disparities between EU and ASEAN. Despite such differences between EU and ASEAN, the study of the development of EU’s Open Skies is expected to provide some implications to the success of OSA in ASEAN. The case of the EU should be taken into consideration even though the two regions differ in some aspects. This should help ASEAN prevent and avoid any difficulties that the EU had encountered during the development of its liberalization of aviation market.

Operation of networked multi-carrier microgrid considering demand response

PurposeMicrogrids are inclined to use renewable energy resources within the availability limits. In conventional studies, energy interchange among microgrids was not considered because of one-directional power flows. Hence, this paper aims to study the optimal day-ahead energy scheduling of a centralized networked multi-carrier microgrid (NMCMG). The energy scheduling faces new challenges by inclusion of responsive loads, integration of renewable sources (wind and solar) and interaction of multi-carrier microgrids (MCMGs).Design/methodology/approachThe optimization model is formulated as a mixed integer nonlinear programing and is solved using GAMS software. Numerical simulations are performed on a system with three MCMGs, including combined heat and power, photovoltaic arrays, wind turbines and energy storages to fulfill the required electrical and thermal load demands. In the proposed system, the MCMGs are in grid-connected mode to exchange power when required.FindingsThe proposed model is capable of minimizing the system costs by using a novel demand side management model and integrating the multiple-energy infrastructure, as well as handling the energy management of the network. Furthermore, the novel demand side management model gives more accurate optimal results. The operational performance and total cost of the NMCMG in simultaneous operation of multiple carriers has been effectively improved.Originality/valueIntroduction and modeling of the multiple energy demands within the MCMG. A novel time- and incentive-based demand side management, characterized by shifting techniques, is applied to reshape the load curve, as well as for preventing the excessive use of energy in peak hours. This paper analyzes the need to study how inclusion of multiple energy infrastructure integration and responsive load can impact the future distribution network costs.

Operational Problems of Ethylene Transport by LPG Gas Carriers

Abstract Ethylene is one of the basic raw materials of the petrochemical industry used for the production of plastics, mainly plastic packaging. The USA is the largest producer of this compound. The enormous increase in demand for Ethylene has been observed in recent years in China as well as in the Middle and Far East. This caused an unprecedented increase in the demand for transport of this cargo by sea. Ethylene carriers for its transport are special construction LPG vessels, having a cascade cycle with Propylene medium (less often the refrigerant R 404 A). They have been designed in such a way as to withstand a working pressure of up to 5.4 bar, and the minimum temperature of the transported load is minus 104°C for fully cooled Ethylene. This cargo is explosive in the mixture with air (within concentrations of 2.75-2.6%) and during heating under elevation pressure. Therefore, it is required to transport Ethylene in with an inert gas, most often Nitrogen. During the operation of LPG carriers carrying Ethylene, processes of aeration, inerting, gassing-up, cooling tanks and a cargo are repeatedly carried out. The most problematic to carry is gassing-up operation, because it is associated with significant amounts of Ethylene loss, this causes large financial losses. In the article, the authors attempted to diagnose the most serious problems during carrying out the most important for cargo loss the cargo handling operations.

Regulatory gaps between LNG carriers and LNG fuelled ships

Given a number of marine vessels treating the liquefied natural gas either as cargo or fuel, this paper examined the regulatory gaps of two different international Codes – the International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk and the International Code of Safety for Ships Using Gases or Other Low-flashpoint Fuels – from the regulatory standpoint. Results of the gap analysis have identified and discussed the key areas encountered with regulatory discrepancies or ambiguities that might interrupt the proper design, construction and operation of LNG carrier and LNG fuelled ship. A systematic investigation and harmonisation process across the Codes was proposed to mitigate the potential issues that may arise from the discordant regulations. Also, the International Maritime Organization was suggested to take proactive action to improve such dissonances while a general insight into the importance of filling those gaps was provided for rule-makers and stakeholders.

The Impact of Using Mega Containerships on Operation and Management of Shipping Lines

Abstract The container shipping industry has undergone a substantial structural alteration recently, the main cause of which stems from the enlargement of ship sizes. Previous research on the topic lacked the discussion of the impact of an upsizing policy on the inner operation and management of carriers. Through cognition agreement and decision importance, this study investigated 32 factors that may affect industrial experts whose companies own or order mega containerships. The results of this investigation reveal that cash-flow control, increasing profits, increasing feeders to collect cargo, and gaining competitive advantage are the most determinant factors that affect decision making. European carriers are more concerned than Asian carriers about the potential safety risks in navigation and the trend of persistently ordering megaships. Asian carriers recognize the decreased agility of megaship deployment but strongly dissent from European carriers.