Optimal control of pulse compensators of oscillatory phenomena in a network oil and gas pipeline system

Within the framework of oil and gas engineering, the problem of optimal control of pulse compensators that counteract harmful oscillatory phenomena in a continuous medium during transportation via network gas-hydraulic carriers is considered. Powerful compressor units that create high pressure in the carrier of a continuous medium, to a large extent contribute to the formation of undesirable oscillatory phenomena (pulsations) that occur at the output of these compressors. These ripples are transmitted to the network carrier environment, which significantly reduces the efficiency of compressor units and even causes accidents in the networks of gas and hydraulic carriers. The latter means that the software engineering of the oil and gas industry should include research in the direction of improving the reliability of operation of compressor units and gas-hydraulic carriers. In the presented study, the mathematical description of the oscillatory process of a continuous medium is carried out by formalisms of a differential-difference system of hyperbolic equations with distributed parameters on a graph. At the same time, the mathematical model contains a fairly accurate mathematical description of controlled pulse compensators. The problem of controlling pulse compensators of an oscillatory process is considered as the problem of a point control action on a controlled differential-difference system at the places where continuous medium vibration dampers are connected to a network carrier. This is a characteristic feature of the presented study, which is quite often used in practice when engineering the processes of transporting various kinds of continuous media through network oil and gas carriers. The study essentially uses the conjugate state and the conjugate system for a differential-difference system - the relations determining the optimal point control are obtained. The results of the work are applicable in the framework of oil and gas engineering to the study of issues of stabilization and parametric optimization.

Design of electric power emergency communication system based on multi-network integration

Natural disasters and emergencies generally pose serious threats to power facilities. Therefore, it is necessary to establish an efficient electric power emergency communication (EPEC) system. Existing systems based on a single network carrier (for example,4G, satellite, and Wi-Fi) may not meet the requirements of complex environments. We design a new EPEC system based on multi-network convergence technology by integrating the above three network carriers. It overcomes the limitations of single network carrier and improves the efficiency of power emergency communication. The test results show that the system can improve the transmission line bandwidth, automatically switch to the optimal signal network, and guarantee the security and stability of data transmission.

Evolution of Air Transport Networks under Different Airline Business Models: The Case of Three Chinese Airlines

This study was conducted to compare the evolution process of air transport networks (ATNs) under different airline business models, and empirically analyzed the causes of evolution differences combining with airline market behaviors. Three representative Chinese airlines (China Southern Airlines, Spring Airlines, and Lucky Air) that belong to three business models (full-service, low-cost, and regional) were examined. Based on mathematical statistics and complex network theory, from spatial pattern, topological feature and central city, the result showed that the airlines have their own unique evolution characteristics of ATNs driven by different business models. China southern airlines as state-owned full-service network carrier, its ATN is easily affected by national policy. Spring Airlines has more flexible and diverse choice in choosing target markets and the ATN had a transformation from a mono-centric divergence network to a two-centric regional one. Lucky Air as a regional feeder carrier, whether navigable airports or navigable routes increasingly concentrated within the southwest of China. This information is important for government to improve the national ATN by developing targeted airlines.

Throughput Analysis of IEEE 802.11 WLANs with Inter-Network Interference

Recently, we often see the environment where many one-to-one Wireless Local Area Networks (WLANs) exist in a small area. In this environment, the network throughput of certain WLAN reduces significantly because of the interference from other networks (i.e., inter-network interference). The inter-network interference is the effect of carrier-sensing activities when there are ongoing transmissions in neighbor networks. This paper presents analytical expressions using airtime concept, which newly take into account the inter-network interference, for network throughputs of WLANs. There are existing works that similarly address the WLAN’s carrier-sensing duration. However, they either consider a simple interference model or assume the simultaneous transmission time is negligible. Different from them, we consider the significant impact of simultaneous transmission. As a result, our analytical model can precisely express each network carrier-sensing duration by subtracting the simultaneous transmission time. More specifically, we have successfully obtained each network throughput by expressing frame-existence probabilities concerning each network’s End Device (ED). We also confirm the validity of the analysis by comparison with simulation. The analytical results and the simulation results agree well.

Central Transportation Port (CPK) – Market Analysis

The Project of Polish Central Transportation Port (CPK), which has already started, will be of the utmost importance for the whole Polish Transportation System. In addition, the cost of this investment is unprecedented. According to the current estimates the cost will surpass 100 billion Zlotys which means around 23.5 billion EUR. The success of CPK will depend on one condition that it becomes a great international hub. This is possible only if LOT Polish Airlines grows into one of the very few European and then global leaders in intercontinental air traffic. Such growth would, however, be against current strong and stable market trends. The most important is a consolidation trend. The effect of this trend is a growing market power of giants and marginalization or even bankruptcy of small and medium size airlines. Smaller carriers have good chances of survival - or even growth - if they find a stable market niche, which gives them protection from the competitors and market crises. In the process of consolidation an important role is played by Joint Venture Agreements. The parties to them suspend competition and behave in the markets as if they had the same owner. For the medium size network carriers the new and very dangerous market trend has already started. The low cost carriers are developing their intercontinental networks. According to the authors of the Project the great chances of market success of LOT Polish Airlines and CPK are created by the fact that in Central and Eastern Europe there is no dominating network carrier and this market is waiting for a leader. In our report we prove that according to the strong and reliable market data the Lufthansa Group is a dominant network carrier in CEE. To be successful LOT would have to take a large part of their market share. But even that will not be enough. LOT would have to dramatically increase its market share in Western Europe for transit traffic between Asia and Europe.

Project Planning for Opening New Destinations for Global Air Carriers

<em>Announcing new flight routes for promising overseas destinations is a sign of stepping into global business for airlines. Opening new flight lines means expanding the product line for any airline. New destinations in turn mean gaining new customers while retaining the existing ones. That is the main reason why global airlines continually seek for new destinations to extend their flight network. This process is a very complex one with a lot tasks and resource requirements. The projected opening date sets the deadline for all the activities. Project management principles needs to be employed to meet these deadlines in order not to experience any delay. To illustrate this problem a new destination project for Turkish Airlines (THY) is explored in detail. THY, as a global network carrier, is planning to expand its operations spectrum and in achieving that makes intensive use of PERT method. This process is illustrated briefly in the paper.</em>

The Strategic Deployment of the Airbus A350-900XWB Aircraft in a Full-Service Network Carrier Route Network: The Case of Singapore Airlines

In the global airline industry, an airline’s fleet routing affects its profitability, level of service and its competitive position. Using a qualitative research approach, this paper examines Singapore Airlines Airbus A350-900XWB fleet deployment and route network development for the period 2016 to 2018. The qualitative data was examined using document analysis. The study found that Singapore Airlines has deployed the Airbus A350-900XWB aircraft on new air routes from Singapore to Cape Town via Johannesburg, Düsseldorf and Stockholm via Moscow and return. The Airbus A350-900XWB aircraft are also replacing older, less efficient aircraft as part of the company’s fleet modernization strategy. Singapore Airlines is also acquiring the new ultra-long-range variant of the Airbus A350-900XWB for use on its proposed new non-stop services from Singapore to Los Angeles and Newark Liberty Airport in New Jersey, USA. The longest flight stage length is the Singapore to San Francisco route which is 7339 nautical miles (13,594 km) in length. The shortest stage length is between Singapore and Kuala Lumpur (160 nautical miles or 297 km). The new non-stop services from Singapore to Los Angeles and New York City will be the longest non-stop services operated by Singapore Airlines. The flight stage lengths between Singapore and Los Angeles and Singapore and Newark Liberty Airport are 7621 nautical miles (14,114 km) and 8285 nautical miles (15,344 km), respectively. The greatest number of available seat kilometers (ASKs) are generated on Singapore Airlines Airbus A350-900 XWB service from Singapore to San Francisco (3.57 million ASKs). The smallest number of ASKs produced are on the short-haul service from Singapore to Kuala Lumpur (75,141 ASKs).