Information Support Technology of Ship Survey Based on Case-based Reasoning

Recently, the significance of ship inspections hasbeen increasingly recognized because sea pollution andsafety problems are occurring more and more frequently. However, current ship inspections rely on the experience ofthe workers. Therefore, it is difficult to understand, and hence to improve, the state of ship inspections. The present problemsare that the ship inspection technical support level in China is not balanced, especially as to the current situation with low level, poor technologyin under-developed areas. In this paper, the case technology about the case-based reasoning to the ship inspection is proposed. The methods of normative inspection case representation are discussed.This is considered to be the basis of case-based reasoning. Then the tertiary case structure with the index is defined, in which the K-nearest neighbor method to calculate the similarity between caseswas used so that the ship’s inspection information can be searched effectively. In addition, animproved retrievalstrategy of the nearest neighbor method is introduced. Therefore, in the inspection site,the inspectors can acquire support information by the case bases, and then the new cases are calculated automatically. Further, a ship inspection case managementwereintroduced to improve the stability of the system. By carrying the case-based reasoning into an inspection, an inspector can generate fault information and inspection information simply and easily. Some examples of the organization and retrieval are shown at the end of the paper

DYNAMIC EXTENSION OF NETWORK FOR CYBER AND COMMUNICATION

CubeSat-backboned networks maybe the key in providing access to highly dynamic networks since they are cost effective and durable. In this thesis, we examine the efficiency of a CubeSat network for an operational area with multiple unmanned aerial vehicles as relays. Also, we assume the vehicles are equipped with directed antenna technology. A successful communication link between the CubeSat and ground nodes is established using commercial off-the-shelf components. From our research results, we conclude that an advancement in directed antenna technology and more capable commercial-of-the-shelf transceivers are needed to achieve faster, more reliable, and more secure networks.Lieutenant Junior Grade, Turkish NavyApproved for public release; distribution is unlimited

Прецедентний метод визначення розпливчатих меж безпечних областей у разі спільного руху засобів пересування

The case-based assessment method of determining the vague boundaries of safety domains inuncertainty situations using the rough set approach is considered. The construction of spatialconfigurations are described, method of determining the spatio-temporal similarity function is proposed.The proposed method is not sensitive to imprecise and incomplete observations due to using the roughsets to determine dynamic safety domainsРассмотрен прецедентный метод оценивания для определения расплывчатых границ областей безопасности вситуациях неопределенности с использованием подхода на основе приближенных множеств. Описано построение пространственных конфигураций, предложен способ определения пространственно-временнойфункции сходства. Предложенный метод является не чувствительным к неточным и неполным наблюдениям вследствие использования приближенных множеств для определения динамических доменов безопасностиРозглянуто прецедентний метод оцінювання для визначення розпливчатих меж областей безпеки в ситуаціях невизначеності з використанням підходу на основі наближених множин. Описано побудову просторових конфігурацій, запропоновано спосіб визначення просторово-часової функції подібності. Запропонований метод є не чутливим до неточних і неповних спостережень внаслідок використання наближених множин для визначення динамічних доменів безпек

Fuzzy Reasoning as a Base for Collision Avoidance Decision Support System

Despite the generally high qualifications of seafarers, many maritime accidents are caused by human error; such accidents include capsizing, collision, and fire, and often result in pollution. Enough concern has been generated that researchers around the world have developed the study of the human factor into an independent scientific discipline. A great deal of progress has been made, particularly in the area of artificial intelligence. But since total autonomy is not yet expedient, the decision support systems based on soft computing are proposed to support human navigators and VTS operators in times of crisis as well as during the execution of everyday tasks as a means of reducing risk levels.This paper considers a decision support system based on fuzzy logic integrated into an existing bridge collision avoidance system. The main goal is to determine the appropriate course of avoidance, using fuzzy reasoning

Medium access control, error control and routing in underwater acoustic networks: a discussion on protocol design and implementation

The journey of underwater communication which began from Leonardo’s era took four and a half centuries to find practical applications for military purposes during World War II. However, over the last three decades, underwater acoustic communications witnessed a massive development due to the advancements in the design of underwater communicating peripherals and their supporting protocols. Successively, doors are opened for a wide range of applications to employ in the underwater environment, such as oceanography, pollution monitoring, offshore exploration, disaster prevention, navigation assistance, monitoring, coastal patrol and surveillance. Different applications may have different characteristics and hence, may require different network architectures. For instance, routing protocols designed for unpartitioned multi-hop networks are not suitable for Delay-Tolerant Networks. Furthermore, single-hop networks do not need routing protocols at all. Therefore, before developing a protocol one must study the network architecture properly and design it accordingly. There are several other factors which should also be considered with the network architecture while designing an efficient protocol for underwater networks, such as long propagation delay, limited bandwidth, limited battery power, high bit error rate of the channel and several other adverse properties of the channel, such as, multi-path, fading and refractive behaviors. Moreover, the environment also has an impact on the performance of the protocols designed for underwater networks. Even temperature changes in a single day have an impact on the performance of the protocols. A good protocol designed for any network should consider some or all of these characteristics to achieve better performance. In this thesis, we first discuss the impact of the environment on the performance of MAC and routing protocols. From our investigation, we discover that even temperature changes within a day may affect the sound speed profile and hence, the channel changes and the protocol performance vary. After that we discuss several protocols which are specifically designed for underwater acoustic networks to serve different purposes and for different network architectures. Underwater Selective Repeat (USR) is an error control protocol designed to assure reliable data transmission in the MAC layer. One may suspect that employing an error control technique over a channel which already suffers from long propagation delays is a burden. However, USR utilizes long propagation by transmitting multiple packets in a single RTT using an interlacing technique. After USR, a routing protocol for surveillance networks is discussed where some sensors are laid down at the bottom of the sea and some sinks are placed outside the area. If a sensor detects an asset within its detection range, it announces the presence of intruders by transmitting packets to the sinks. It may happen that the discovered asset is an enemy ship or an enemy submarine which creates noise to jam the network. Therefore, in surveillance networks, it is necessary that the protocols have jamming resistance capabilities. Moreover, since the network supports multiple sinks with similar anycast address, we propose a Jamming Resistance multi-path Multi-Sink Routing Protocol (MSRP) using a source routing technique. However, the problem of source routing is that it suffers from large overhead (every packet includes the whole path information) with respect to other routing techniques, and also suffers from the unidirectional link problem. Therefore, another routing protocol based on a distance vector technique, called Multi-path Routing with Limited Cross-Path Interference (L-CROP) protocol is proposed, which employs a neighbor-aware multi-path discovery algorithm to support low interference multiple paths between each source-destination pair. Following that, another routing protocol is discussed for next generation coastal patrol and surveillance network, called Underwater Delay-Tolerant Network (UDTN) routing where some AUVs carry out the patrolling work of a given area and report to a shore based control-center. Since the area to be patrolled is large, AUVs experience intermittent connectivity. In our proposed protocol, two nodes that understand to be in contact with each other calculate and divide their contact duration equally so that every node gets a fair share of the contact duration to exchange data. Moreover, a probabilistic spray technique is employed to restrict the number of packet transmissions and for error correction a modified version of USR is employed. In the appendix, we discuss a framework which was designed by our research group to realize underwater communication through simulation which is used in most of the simulations in this thesis, called DESERT Underwater (short for DEsign, Simulate, Emulate and Realize Test-beds for Underwater network protocols). It is an underwater extension of the NS-Miracle simulator to support the design and implementation of underwater network protocols. Its creation assists the researchers in to utilizing the same codes designed for the simulator to employ in actual hardware devices and test in the real underwater scenario

Hybrid approaches for mobile robot navigation

The work described in this thesis contributes to the efficient solution of mobile robot navigation problems. A series of new evolutionary approaches is presented. Two novel evolutionary planners have been developed that reduce the computational overhead in generating plans of mobile robot movements. In comparison with the best-performing evolutionary scheme reported in the literature, the first of the planners significantly reduces the plan calculation time in static environments. The second planner was able to generate avoidance strategies in response to unexpected events arising from the presence of moving obstacles. To overcome limitations in responsiveness and the unrealistic assumptions regarding a priori knowledge that are inherent in planner-based and a vigation systems, subsequent work concentrated on hybrid approaches. These included a reactive component to identify rapidly and autonomously environmental features that were represented by a small number of critical waypoints. Not only is memory usage dramatically reduced by such a simplified representation, but also the calculation time to determine new plans is significantly reduced. Further significant enhancements of this work were firstly, dynamic avoidance to limit the likelihood of potential collisions with moving obstacles and secondly, exploration to identify statistically the dynamic characteristics of the environment. Finally, by retaining more extensive environmental knowledge gained during previous navigation activities, the capability of the hybrid navigation system was enhanced to allow planning to be performed for any start point and goal point

МОДЕЛЬ СЦЕНАРНО-ПРЕЦЕДЕНТНОГО КЕРУВАННЯ СПІЛЬНИМ РУХОМ ВЕЛИКИХ ГЕТЕРОГЕННИХ АНСАМБЛІВ БЕЗПІЛОТНИХ АПАРАТІВ У РЕАЛЬНОМУ ЧАСІ

В статті розглянуто особливості керування одночасним рухом великої групи безпілотних апаратів, що рухаються у спільному З-D просторі в межах різних середовищ. Розроблено модель керування спільним рухом гетерогенних ансамблів безпілотних апаратів у реальному часі за допомогою гібридної динамічної сценарно- прецедентної системи та представлено архітектуру прототипу цієї системи. Запропонована система керування спі­льним рухом є частиною складної бортової системи управління безпілотним апаратом, що може пілотувати його за певною траєкторією, яка визначається сценарієм, відповідним до ролі даного безпілотного апарату у ансамблі, його місії та поточної просторової конфігурації, що має відповідає умовам безпеки. Для вирішення задачі викорис­тано методи сценарно-прецедентного підходу, отримання висновків на основі моделей, та перевірки дотримання обмежень. Новизна запропонованого підходу полягає у розробці гібридної моделі сценарно-прецедентного пошуку рішень, що заснована на принципах пасивного керування, та комбінує сценарно-прецедентний пошук рішень з їх адаптацією на основі кінематичних моделей та верифікацією з перевіркою дотримання заданих обмежень. Модель має обчислювальну складність, яка слабко залежить від числа динамічних об'єктів, які одночасно рухаються, та є працездатною у З-D просторі. Практична значимість запропонованого підходу полягає в тому, що він дає можли­вість вирішувати задачу керування спільним рухом безпілотних апаратів у гетерогенних ансамблях в умовах реа­льного часу, змінюючи призначені сценарії активності «на льоту», замінюючи, додаючи або видаляючи певні послі­довності дій та синхронізуючи їх у часі та просторі, що дозволяє безпілотним апаратам спільно маневрувати, уни­каючи зіткнень, перешкод тощо. Це дозволяє отримувати адекватні і своєчасні реакції ансамбля безпілотних апа­ратів на динамічні та ситуаційні збурення, що їх зазнають окремі безпілотники внаслідок непередбачуваності сере­довища. Запропонований підхід суттєво зменшує обчислювальну складність вирішення задачі. Спираючись на опис поточної просторової конфігурації та використовуючи кінематичну модель безпілотних апаратів, він дозволяє отримувати елементи безпечних траєкторій безпілотників, що входять до гетерогенного ансамблю, та які макси­мально підтримують задану структурну та геометричну конфігурацію й компенсують виникаючі збурення

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids