Implementation of a new replacement method in WMN-PSO simulation system and its performance evaluation

(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.With the fast development of wireless technologies, Wireless Mesh Networks (WMNs) are becoming an important networking infrastructure due to their low cost and increased high speed wireless Internet connectivity. In our previous work, we implemented the Linearly Decreasing Vmax Method (LDVM) for our WMN-PSO simulation system. In this paper, we implement a new replacement method for mesh routers called Rational Decrement of Vmax Method (RDVM). We use Size of Giant Component (SGC) and Number of Covered Mesh Clients (NCMC) as metrics for optimization. From the simulation results, we found that RDVM converges faster to best solution than LDVM.Peer ReviewedPostprint (author's final draft

Object-based Information Flow Control in Peer-to-peer Publish/Subscribe Systems

Distributed systems are getting so scalable like IoT (Internet of Things) and P2P (Peer-to-Peer) systems that millions of devices are connected and support various types of applications. Here, distributed systems are required to be secure in addition to increasing the performance, reliability, and availability and reducing the energy consumption. In distributed systems, information in objects flows to other objects by transactions reading and writing data in the objects. Here, some information of an object may illegally flow to a subject which is not allowed to get the information of the object. Especially, a leakage of sensitive information is to be prevented from occurring. In order to keep information systems secure, illegal information flow among objects has to be prevented. Types of synchronization protocols are so far discussed based on read and write access rights in the RBAC (Role-Based Access Control) model to prevent illegal information flow.In this thesis, we newly propose a P2PPSO (P2P type of topic-based PS (Publish/Subscribe) with Object concept) model and discuss the models and protocols for information flow control. A P2PPSO model is composed of peer processes (peers) which communicate with one another by publishing and subscribing event messages. Each peer can both publish and receive event messages with no centralized coordinator compared with traditional centralized PS models. Each event message published by a source peer carries information to a target peer. The contents carried by an event message are considered to be composed of objects. An object is a unit of data resource. Objects are characterized by topics, and each event message is also characterized by topics named publication topics.In order to make a P2PPSO system secure, we first newly propose a TBAC (Topic-Based Access Control) model. Here, an access right is a pair ⟨t, op⟩ of a topic t and a publish or subscribe operation op. A peer is allowed to publish an event message with publication topics and subscribe interesting topics only if the publication and subscription access rights are granted to the peer, respectively. Suppose an event message e_j published by a peer p_j carries an object on some topics into a target peer p_i. Here, information in the peer p_j illegally flows to the peer p_i if the target peer p_i is not allowed to subscribe the topics. An illegal object is an object whose topics a target peer is not allowed to subscribe. Even if an event message is received by a target peer by checking topics, objects carried by the event message may be illegal at the target peer. Hence, first, we propose a TOBS (Topics-of-Objects-Based Synchronization) protocol to prevent target peers from being delivered illegal objects in the P2PPSO system. Here, even if an event message is received by a target peer, illegal objects in the event message are not delivered to the target peer.In the TOBS protocol, every event message is assumed to be causally delivered to every common target peer in the underlying network. Suppose an event message e_2 is delivered to a target peer p_i before another event message e_1 while the event message e_1 causally precedes the event message e_2 (e_1 →_c e_2). Here, the event message e_2 is premature at the peer p_i. Hence, secondly, we propose a TOBSCO (TOBS with Causally Ordering delivery) protocol where the function to causally deliver every pair of event messages is added to the TOBS protocol. Here, we assume the underlying network supports reliable communication among every pair of peers, i.e. no event message loss, no duplicate message, and the sending order delivery of messages. Every pair of event messages received by using topics are causally delivered to every common target peer by using the vector of sequence numbers.In the TOBS and TOBSCO protocols, objects delivered to target peers are held as replicas of the objects by the target peers. If a peer updates data of an object, the peer distributes event messages, i.e. update event messages, to update every replica of the object obtained by other peers. If a peer updates an object without changing topics, the object is referred to as altered. Here, an update event message for the altered object is meaningless since peers check only topics to exchange event messages. Hence, thirdly, we propose an ETOBSCO (Efficient TOBSCO) protocol where update event messages of objects are published only if topics of the objects are updated to reduce the network overhead.In the evaluation, first, we show how many numbers of event messages and objects are prevented from being delivered to target peers in the TOBS protocol. Next, we show every pair of event messages are causally delivered but it takes longer to deliver event messages in the TOBSCO protocol than the TOBS protocol. Finally, we show the fewer number of event messages are delivered while it takes longer to update replicas of altered objects in the ETOBSCO protocol than the TOBSCO protocol.博士(工学)法政大学 (Hosei University

Routing Protocols for Underwater Acoustic Sensor Networks: A Survey from an Application Perspective

Underwater acoustic communications are different from terrestrial radio communications; acoustic channel is asymmetric and has large and variable end‐to‐end propagation delays, distance‐dependent limited bandwidth, high bit error rates, and multi‐path fading. Besides, nodes’ mobility and limited battery power also cause problems for networking protocol design. Among them, routing in underwater acoustic networks is a challenging task, and many protocols have been proposed. In this chapter, we first classify the routing protocols according to application scenarios, which are classified according to the number of sinks that an underwater acoustic sensor network (UASN) may use, namely single‐sink, multi‐sink, and no‐sink. We review some typical routing strategies proposed for these application scenarios, such as cross‐layer and reinforcement learning as well as opportunistic routing. Finally, some remaining key issues are highlighted

A service-oriented middleware for integrated management of crowdsourced and sensor data streams in disaster management

The increasing number of sensors used in diverse applications has provided a massive number of continuous, unbounded, rapid data and requires the management of distinct protocols, interfaces and intermittent connections. As traditional sensor networks are error-prone and difficult to maintain, the study highlights the emerging role of “citizens as sensors” as a complementary data source to increase public awareness. To this end, an interoperable, reusable middleware for managing spatial, temporal, and thematic data using Sensor Web Enablement initiative services and a processing engine was designed, implemented, and deployed. The study found that its approach provided effective sensor data-stream access, publication, and filtering in dynamic scenarios such as disaster management, as well as it enables batch and stream management integration. Also, an interoperability analytics testing of a flood citizen observatory highlighted even variable data such as those provided by the crowd can be integrated with sensor data stream. Our approach, thus, offers a mean to improve near-real-time applications

サーバクラスタでの低消費電力化のための移行モデルの研究

博士(工学)法政大学 (Hosei University

Towards a Quality-of-Thing based Approach for Assigning Things to Federations

In the context of an Internet-of-Things (IoT) ecosystem, this paper discusses 2 necessary stages for managing federations of things. The first stage defines things in terms of duties and non-functional properties that define the quality of these duties. And, the second stage uses these properties to assign appropriate things to future federations. Specialized into adhoc and planned, federations are expected to satisfy needs and requirements of real-life situations like traffic control that arise at run-time. A set of experiments using a mix of real and simulated datasets, demonstrate the technical doability of thing assignment to federations and are presented in the paper, as well

Key Requirements for the Detection and Sharing of Behavioral Indicators of Compromise

[EN] Cyber threat intelligence feeds the focus on atomic and computed indicators of compromise. These indicators are the main source of tactical cyber intelligence most organizations benefit from. They are expressed in machine-readable formats, and they are easily loaded into security devices in order to protect infrastructures. However, their usefulness is very limited, specially in terms of time of life. These indicators can be useful when dealing with non-advanced actors, but they are easily avoided by advanced ones. To detect advanced actor¿s activities, an analyst must deal with behavioral indicators of compromise, which represent tactics, techniques and procedures that are not as common as the atomic and computed ones. In this paper, we analyze why these indicators are not widely used, and we identify key requirements for successful behavioral IOC detection, specification and sharing. We follow the intelligence cycle as the arranged sequence of steps for a defensive team to work, thereby providing a common reference for these teams to identify gaps in their capabilities.Villalón-Huerta, A.; Ripoll-Ripoll, I.; Marco-Gisbert, H. (2022). Key Requirements for the Detection and Sharing of Behavioral Indicators of Compromise. Electronics. 11(3):1-20. https://doi.org/10.3390/electronics1103041612011

Comparison of WLAN Probe and Light Sensor-Based Estimators of Bus Occupancy Using Live Deployment Data

Bus company operators are interested in obtaining knowledge about the number of passengers on their buses—preferably doing so at low deployment costs and in an automated manner, while keeping accuracy high. One solution, widely used in practice, involves deploying a light sensor-based system, counting the people entering and leaving the bus. The light sensor system is simple, but errors accumulate over time, because it is not capable of error correcting. For this reason, the light sensor-based system is compared to a WLAN probe-based system, which has entirely different characteristics. Inaccuracy with the WLAN estimator comes from a need to filter out mobile devices outside the bus and to map the number of detected devices to a number of people. The comparison is performed based on data collected from a real-life deployment in a medium sized German city. The comparison shows the trade-off in selecting either of the two methods. Furthermore, a novel approach for fusion of the light sensor and WLAN estimators is proposed which has a big potential in improving accuracy of both estimators. A fusion approach is proposed that utilizes the different error characteristics for error compensation by calculating compensation terms. The knowledge of Ground Truth is not required as part of this fusion approach for calibration; results show that the approach can find the optimal parameter settings and that it makes this occupancy estimation approach scalable and automated

РОЗРОБКА МЕТОДУ КРИПТОКОМПРЕСІЙНОГО КОДУВАННЯ ЗОБРАЖЕНЬ НА ОСНОВІ ПЛАВАЮЧОЇ НЕДЕТЕРМІНОВАНОЇ СХЕМИ ОБРОБКИ

In the process of managing the objects of crisis infrastructure and during their protection, digital video images are used. Their volumes are constantly growing and requirements are imposed on them to maintain maximum quality while maintaining confidentiality. Therefore, a scientific and applied problem is relevant, which consists in increasing the confidentiality of video information in the conditions of ensuring its reliability and availability. To solve it, the one-stage method of cryptocompression coding of images in a differentiated basis based on the use of non-equilibrium positional coding technology was further improved. The difference between this method and the known ones is as follows. First, the floating coding scheme is organized within the entire image plane, when image elements belonging to different blocks of video data participate in the formation of the code values of the information component. For this, a scheme has been developed for linearizing coordinates from a four-dimensional representation of an element in a two-dimensional matrix, which determine the coordinates of a block in the image plane and coordinates of an element in this block, into a one-dimensional coordinate for one-to-one representation of this element in a vector. Secondly, two degrees of uncertainty are additionally used, which consist of the non-deterministic length of the code values of the cryptocompression codograms and the non-deterministic number of elements involved in their formation. This makes it possible to increase the cryptographic strength and availability of video data without loss of credibility.В процессе управления объектами кризисной инфраструктуры и во время их охраны используются цифровые видеоизображения. Их объемы постоянно растут и к ним предъявляются требования относительно сохранения максимального качества при необходимости обеспечения конфиденциальности. Поэтому актуальной является научно-прикладная проблема, которая заключается в повышении конфиденциальности видеоинформации в условиях обеспечения ее достоверности и доступности. Для ее решения получил дальнейшее совершенствование однокаскадный метод криптокомпрессионного кодирования изображений в дифференцированном базисе на основе использования технологии неравновесного позиционного кодирования. Отличие данного метода от известных заключается в следующем. Во-первых, плавающая схема кодирования организуется в пределах всей плоскости изображения, когда в формировании кодовых величин информационной составляющей участвуют элементы изображения, принадлежащие разным блокам видеоданных. Для этого разработана схема линеаризации координат с четырехмерного представления элемента в двумерной матрице, которые определяют координаты блока в плоскости изображения и координаты элемента в этом блоке, в одномерную координату для взаимно-однозначного представления этого элемента в векторе. Во-вторых, дополнительно используются две степени неопределенности, которые состоят из недетерминированной длины кодовых значений криптокомпрессионных кодограмм и недетерминированного количества элементов, участвующих в их формировании. Это позволяет повысить криптостойкость и доступность видеоданных без потери достоверности.В процесі управляння об'єктами кризової інфраструктури та під час їх охорони використовуються цифрові відеозображення. Їх обсяги постійно зростають та до них висуваються вимоги щодо збереження максимальної якості при необхідності забезпечення конфіденційності. Тому, актуальною є науково-прикладна проблема, яка полягає в підвищенні конфіденційності відеоінформації в умовах забезпечення її достовірності та доступності. Для її вирішення отримав подальше вдосконалення однокаскадний метод криптокомпресійного кодування зображень в диференційованому базисі на основі використання технології нерівноважного позиційного кодування. Відмінність даного методу від відомих полягає в наступному. По-перше, плаваюча схема кодування організується в межах всієї площині зображення, коли у формуванні кодових величин інформаційної складової беруть участь елементи зображення, що належать різним блокам відеоданих. Для цього розроблена схема лінеаризації координат з чотиривимірного представлення елементу в двовимірної матриці, які визначають координати блоку в площині зображення та координати елементу в цьому блоці, в одновимірну координату для взаємно-однозначного уявлення цього елемента у векторі. По-друге, додатково використовуються два ступеня невизначеності, які складаються з недетермінованої довжини криптокомпресійних кодограм і недетермінованої кількості елементів, що беруть участь в їх формуванні. Це дозволяє підвищити криптостійкість та доступність відеоданих без втрати достовірності

Opinion Mining for Software Development: A Systematic Literature Review

Opinion mining, sometimes referred to as sentiment analysis, has gained increasing attention in software engineering (SE) studies. SE researchers have applied opinion mining techniques in various contexts, such as identifying developers’ emotions expressed in code comments and extracting users’ critics toward mobile apps. Given the large amount of relevant studies available, it can take considerable time for researchers and developers to figure out which approaches they can adopt in their own studies and what perils these approaches entail. We conducted a systematic literature review involving 185 papers. More specifically, we present 1) well-defined categories of opinion mining-related software development activities, 2) available opinion mining approaches, whether they are evaluated when adopted in other studies, and how their performance is compared, 3) available datasets for performance evaluation and tool customization, and 4) concerns or limitations SE researchers might need to take into account when applying/customizing these opinion mining techniques. The results of our study serve as references to choose suitable opinion mining tools for software development activities, and provide critical insights for the further development of opinion mining techniques in the SE domain