Showing papers in "International Journal of Computer Network and Information Security in 2011"

Comprehensive Study of Selective Forwarding Attack in Wireless Sensor Networks

Abstract: Sensor networks are becoming closer towards wide-spread deployment so security issues become a vital concern. Selective forwarding attack is one of the harmful attacks against sensor networks and can affect the whole sensor network communication. The variety of defense approaches against selective forwarding attack is overwhelming. In this paper we have described all the existing defensive schemes according to our best knowledge against this attack along with their drawbacks, thus providing researchers a better understanding of the attack and current solution space. This paper also classifies proposed schemes according to their nature and defense. Nature of scheme classifies into Distributed and Centralized. Defense of scheme classifies into detection and prevention. Index Terms – Selective Forwarding Attack, Sensor

Survey on Opportunistic Routing in Multihop Wireless Networks

Abstract: Opportunistic routing is based on the use of broadcast transmissions to expand the potential forwarders that can assist in the retransmission of the data pack ets. The receptors need to be coordinated in order to avoid duplicated transmissions. This is usually achieved by ordering the forwarding nodes according to some criteria. The proposed opport unistic routing protocols differ in the criterion to order the receptors and the way the receptors coordinate. This paper presents a survey of the most significant opportunistic routing protocols for multihop wireless networks.

Measuring Corporate Social Responsibility Based on a Fuzzy Analytical Hierarchy Process

Abstract: With increasing social awareness on the issue of corporate social responsibility (CSR), the measurement of CSR has received considerable attention in both academic literature and managerial practice. Following a review of CSR theory development and the literature on measures of CSR, this paper proposes a systematic approach to measure CSR using fuzzy analytical hierarchy process (FAHP). In addition, a preliminary investigation is presented to explain how the approach can help in evaluating CSR in practice.

A New Protocol for Detecting Black Hole Nodes in Ad Hoc Networks

Abstract: An ad hoc network is a collection of infrastructure less nodes, cooperating dynamically to form a temporary network which meets certain immediate needs. The lack of in frastructure implies that the nodes are connected peer-to-peer. Therefore, each node acts as a router beside its main role as a hos t. With the increased number of mobile devices, the application s of ad hoc network increased dramatically to capture different domains such as: academic communication, and mobile conferencing beside its traditional domains such as: military communication , and emergency communication. Security issues become more challenging in ad hoc n etwork due to its dynamic nature which allows any node to freely join as well as leave the network without having a physical address or getting permission. Ad hoc networks are vulnerable to diffe rent kinds of attacks such as: denial of services, impersonation, and eavesdropping. This paper discusses one of the security problems i n ad hoc networks called the black hole problem. It occurs w hen a malicious node referred as black hole joins the network. The black hole conducts its malicious behavior during the process of route discovery. For any received RREQ, the black hole cl aims having a route and propagates a faked RREP. The source node responds to these faked RREPs and sends its data through the re ceived routes. Once the data is received by the black hole, it is dropped instead of being sent to the desired destination. The proposed protocol is built on top of the origin al AODV. It extends the AODV to include the following functionalities: source node waits for a reliable route; each node has a ta ble in which it adds the addresses of the reliable nodes; RREP is o verloaded with an extra field to indicate the reliability of the r eplying node. The simulation of the proposed protocol shows significa nt improvement in the terms of: packet delivery ratio, number of d ropped packets, and end-to-end delay. The overhead still needs more researches .

Design for 5G Mobile Network Architecture

Abstract: In this paper we propose a new design solution for network architecture of future 5G mobile networks. The proposed design is based on user-centric mobile environment with many wireless and mobile technologies on the ground. In heterogeneous wireless environment changes in all, either new or older wireless technologies, is not possible, so each solution towards the next generation mobile and wireless networks should be implemented in the service stratum, while the radio access technologies belong to the transport stratum regarding the Next Generation Networks approach. In the proposed design the user terminal has possibility to change the Radio Access Technology - RAT based on certain criteria. For the purpose of transparent change of the RATs by the mobile terminal, we introduce so-called Policy-Router as node in the core network, which establishes IP tunnels to the mobile terminal via different available RATs to the terminal. The selection of the RAT is performed by the mobile terminal by using the proposed user agent for multi-criteria decision making based on the experience from the performance measurements performed by the mobile terminal. For the process of performance measurements we introduce the QoSPRO procedure for control information exchange between the mobile terminal and the Policy Router.

Survey on Incremental Approaches for Network Anomaly Detection

Abstract: As the communication industry has connected distant corners of the globe using advances in network technology, intruders or attackers have also increased attacks on networking infrastructure commensurately. System administrators can attempt to prevent such attacks using intrusion detection tools and systems. There are many commercially available signature-based Intrusion Detection Systems (IDSs). However, most IDSs lack the capability to detect novel or previously unknown attacks. A special type of IDSs, called Anomaly Detection Systems, develop models based on normal system or network behavior, with the goal of detecting both known and unknown attacks. Anomaly detection systems face many problems including high rate of false alarm, ability to work in online mode, and scalability. This paper presents a selective survey of incremental approaches for detecting anomaly in normal system or network traffic. The technological trends, open problems, and challenges over anomaly detection using incremental approach are also discussed.

Improving Reliability of Jamming Attack Detection in Ad hoc Networks

Abstract: Defense against denial of service (DoS) attacks is a critical component of any security system as these attacks can affect the availability of a node or an entire network. In this work, we focus on jamming type DoS attacks at the physical a nd MAC layers in 802.11 based ad hoc networks. Collisions in wirel ess networks occur due to varying factors such as jamming attack s, hidden terminal interferences and network congestion. We p resent a probabilistic analysis to show that collision occur rence alone cannot be used to conclusively determine jamming attacks i n wireless channel. To increase the reliability of attack dete ction, it is necessary to provide enhanced detection mechanisms that can determine the actual cause of channel collisions. T o address this, we first investigate the problem of diagnosing the pres ence of jamming in ad hoc networks. We then evaluate the detection mechanism using cross-layer information obtained from physica l and link layers to differentiate between jamming and congest ed network scenarios. By correlating the cross-layer data with collision detection metrics, we can distinguish attack scenar ios from the impact of traffic load on network behavior. Through simulation results we demonstrate the effectiveness of our sch eme in detecting jamming with improved precision.

Survey of Reactive and Hybrid Routing Protocols for Mobile Ad Hoc Networks

Abstract: Mobile Ad Hoc Networks (MANETs) are wireless communication networks that operate without the need for any infrastructure They are characterized by challenging environments; where the nodes are in constant motion, bandwidth and other resources are limited and the transmission medium prone to errors and collisions Since wireless transmission ranges are limited, data often has to be relayed through multiple hops, which is why routing protocols are necessary to determine the best routes to send data across There are numerous MANET routing protocols, categorized in different ways This paper presents an overview of MANETs routing issues as well as a detailed discussion of the operating principles behind a few selected routing protocols and their relative performance

A Model of Workflow-oriented Attributed Based Access Control

Abstract: —the emergence of “Internet of Things” breaks previous traditional thinking, which integrates physical infrastructure and network infrastructure into unified infrastructure. There will be a lot of resources or information in IoT, so computing and processing of information is the core supporting of IoT. In this paper, we introduce “Service-Oriented Computing” to solve the problem where each device can offer its functionality as standard services. Here we mainly discuss the access control issue of service-oriented computing in Internet of Things. This paper puts forward a model of Workflow-oriented Attributed Based Access Control (WABAC), and design an access control framework based on WABAC model. The model grants permissions to subjects according to subject atttribute, resource attribute, environment attribute and current task, meeting access control request of SOC. Using the approach presented can effectively enhance the access control security for SOC applications, and prevent the abuse of subject permissions.

A Semantic Context-Based Model for Mobile Web Services Access Control

Abstract: As mobile web services becomes more pervasive, applications based on mobile web services will need flexible access control mechanisms. Unlike traditional approaches based on the identity or role for access control, access decisions for these applications will depend on the combination of the required attributes of users and the contextual information. This paper proposes a semantic context-based access control model (called SCBAC) to be applied in mobile web services environment by combining semantic web technologies with context-based access control mechanism. The proposed model is a context-centric access control solutions, context is the first-class principle that explicitly guides both policy specification and enforcement process. In order to handle context information in the model, this paper proposes a context ontology to represent contextual information and employ it in the inference engine. As well as, this paper specifies access control policies as rules over ontologies representing the concepts introduced in the SCBAC model, and uses semantic web rule language (SWRL) to form policy rule and infer those rules by JESS inference engine. The proposed model can also be applied to context-aware applications. Index Terms—mobile web services, context-based access control, ontology technology, OWL, SWRL

Efficient Proxy Re-encryption with Private Keyword Searching in Untrusted Storage

Abstract: Cloud computing is an important trend that in many ways is beginning to fulfill the early promise of the Internet and creating unanticipated change in computing paradigm. As promising as cloud computing is, this paradigm brings forth new security and privacy challenges when operating in the untrusted cloud scenarios. Motivated by the challenging problem "Private Searching over Encrypted Data", we propose a new cryptographic primitive, Proxy Re-encryption with Private Searching (PRPS for short). The PRPS scheme enables the data users and owners efficiently query and access files stored in untrusted cloud, while keeping query privacy and data privacy from the cloud providers. The concrete construction is based on proxy re-encryption, public key encryption with keyword search and the dual receiver cryptosystem. Extensive analysis shows that our scheme is efficient and semantically secure under the BDH assumption.

Survey of Topology-based Multicast Routing Protocols for Mobile Ad hoc Networks

Abstract: This review paper presents an exhaustive survey on the different categories of topology-based multicast routing protocols that have been proposed for mobile ad hoc networks (MANETs). Due to the inherent broadcast nature of the wireless medium, one- to-many multicast communications are characteristic of most of the MANET applications. MANET multicast routing protocols are primarily classified as tree-based and mesh-based protocols depending on the underlying topology used for communication. Tree-based protocols are further classified to source-tree based and shared-tree based depending on whether the tree is rooted at the multicast source or a common node. Further, there are several sub- categories of source-tree based and shared-tree based multicast routing protocols. The mesh-based multicast protocols are primarily categorized to source-initiated and receiver-initiated protocols depending on which entity (the source node or the receiver nodes) initiates the mesh formation. In this paper, we will explain in detail the working of eleven different multicast routing protocols, covering all of the sub-categories of tree-based and mesh-based routing protocols.

Wireless Network Behavior under ICMP Ping Flood DoS Attack and Mitigation Techniques

Abstract: Internet Control Message Protocol (ICMP) is an erro r reporting and diagnostic utility and it is consider ed as a part of Internet Protocol (IP) suite. Although this protoco l is very important for ensuring correct data distribution, i t can be exploited by malicious users for conducting different Denial of Service (DoS) attacks. Due to the broadcast nature of wireless co mmunication, exploitation of this kind of attack is even easier. By sending bogus ICMP redirect packets, a malicious user can either disrupt or intercept communication from a wireless access poin t. In this paper, we present our approach to simulate the ICMP Ping Flood Attack, and to analyze the effects of th is attack on wireless networks using OPNET Modeler. We propose several countermeasures against this type of attack. Simula tion results regarding the effects of link failure recovery mech anism against this type of attack are discussed .

Identity Authentication and Context Privacy Preservation in Wireless Health Monitoring System

Abstract: Privacy preservation is an important challenge for wireless health monitoring system. This paper analyses the privacy threat types based on the wireless health monitoring system architecture, and built the key system model for identity threat and context privacy preservation based on traffic analysis threat. To resist these threat , the integrated message encryption, identity authentication and traffic context privacy preservation, based on identity-based cryptography(IBC) and identity-based signature(IBS), is carried out at one time during the process of sending, receiving and accessing the patients' health information. Extensive analysis demonstrates the effectiveness of the proposed scheme.

Genetic spectrum assignment model with constraints in cognitive radio networks

Abstract: The interference constraints of genetic spectrum assignment model in cognitive radio networks are analyzed in this paper. An improved genetic spectrum assignment model is proposed. The population of genetic algorithm is divided into two sets, the feasible spectrum assignment strategies and the randomly updated spectrum assignment strategies. The penalty function is added to the utility function to achieve the spectrum assignment strategy that satisfies the interference constraints and has better fitness. The proposed method is applicable in both the genetic spectrum assignment model and the quantum genetic spectrum assignment mode. It can ensure the randomness of partial chromosomes in the population to some extent, and reduce the computational complexity caused by the constraints-free procedure after the update of population. Simulation results show that the proposed method can achieve better performance than the conventional genetic spectrum assignment model and quantum genetic spectrum assignment model

Comparison of IEEE 802.11 and IEEE 802.15.4 for Future Green Multichannel Multi-radio Wireless Sensor Networks

Abstract: Multi-channel MAC protocols have recently obtained considerable attention in wireless network ing research because they promise to increase capacity of wirele ss networks significantly by exploiting multiple frequency band s. In this paper, we do a comparison between IEEE 802.11 and IEEE 802.15.4 and investigate the performance between both using simulations conducted in NS2. This investigation will allow us to determine the feasibility in having IEEE 802.11 being considered as a future medium for wireless sensor networks operating in a multichannel environment at high data rate with streaming data t hat would be a challenge for IEEE 802.15.4. More so IEEE 802.15.4 will be facing severe challenge to operate in the 2.4GHz frequency band when the IEEE 802.11n becomes popular, operating within the same frequency band. We demonstrate through simulations that IEEE 802.11 perform better with high data rate, streaming constant bit rate and at longer range comparing to 802.15.4 which operates better with small data size at much shorter range. The outcome from this paper will be valuable for our future work in designing a multich annel MAC protocol for contention-based 802.11 WSN.

The Analysis and Identification of P2P Botnet’s Traffic Flows

Abstract: As the advance of information and communication technologies, the Internet has become an integral part of human life. Although it can provide us with many convenient services, there also exist some potential risks for its users. For example, hackers may try to steal confidential data for illegal benefits, and they use a variety of methods to achieve the goal of attacks, e.g., Distributed Denial of Service (DDoS), Spam and Trojan. These methods require a large number of computers; hence, hackers often spread out malicious software to infect those computers with lower defense mechanisms. The infected computers will become the zombie computers in the botnets controlled by hackers. Thus, it is an important subject regarding network security to detect and defend against the botnets. Among them, the Peer-to-Peer (P2P) botnet is a new type of botnets with every zombie computer as a peer controlled by hackers and thus its defense is more difficult. The objective of this study is to identify the traffic flows produced by known or unknown malicious software for defending against P2P botnets. Based on the analysis of P2P network's traffic flows and the ASCII distribution in their packets, a mechanism containing six steps was proposed to identify the traffic flows of P2P botnets for locating the zombie computers, and finally restrain the computers from further infection.

Novel Adaptive QoS Provisioning in Heterogeneous Wireless Environment

Abstract: In this paper we introduce novel concept for adapti ve QoS provisioning for multimedia services in wireles s/mobile networks. The concept is proven via simulation anal ysis in integrated environment with 3G and IEEE 802.11 networks. We introduce a new module that provides the best QoS a nd lower cost for a given service by using one or more wireless t echnologies at a given time. The performance of the algorithm is eva luated using simulation with multimode mobile stations. The analysis of this framework has shown overall better performances and QoS provisioning for different multimedia services in a variety of network conditions in heterogeneous wireless enviro nment.

Modeling of Power Line Transfer of Data for Computer Simulation

Abstract: The paper deals with problems of data communication over power lines. This technology is referred to as PLC (Power Line Communication). A wider deployment of this technology in practice is currently hampered by a number of drawbacks. They are, in particular, interference with useful signal on lines, interference radiation, limited range of useful signal, and power grid elements that affect the transfer. It results from an analysis of partial problems that it is of advantage to have available a computer model of power line, which would enable simulating appropriately the data transfer over power lines. Two different, in a way conflicting, requirements need to be reconciled. Primarily, power lines are not designed for data transfer while data lines, in turn, are not adapted for power transmission. Although the two types of line are represented by the same parameters, their operation is completely different. A number of papers have been devoted to potential models of power lines for data communication. The present paper is an attempt to cope with these problems.

Upgrading Efficiency and Improvement of the Performance of Broadband Wireless Optical Access Communication Networks

Abstract: It is commonly agreed that the next generation of wireless optical communication systems, usually referred to as fourth generation systems, will not be based on a single access technique but it will encompass a number of different complementary access technologies. Communication topics such as modulation, multiplexing, and detection are discussed in relation to optical wireless links. Negative channel effects such as dispersion and absorption are investigated with respect to their impact on the channel and the associated bit error rates. The challenges posed by atmospheric disturbances are considered for free space links. As the backbone and the metropolitan area network technologies can increasingly provide unprecedented bandwidth capacities, the focus is being gradually shifted toward broadband access technologies capable of connecting the customer premises to the local exchange. Moreover, power link budgets are prepared for both fiber and wireless optical communication systems to illustrate the optical losses incurred during transmission. This paper proposed new technique for improvement the performance of voice and video signal quality over wireless optical links namely, modified Shannon technique.

A public opinion classification algorithm based on micro-blog text sentiment intensity: Design and implementation

Abstract: on the features of short content and nearly real- time broadcasting velocity of micro-blog information, our lab constructed a public opinion corpus named MPO Corpus. Then, based on the analysis of the status of the network public opinion, it proposes an approach to calculate the sentiment intensity from three levels on words, sentences and documents respectively in this paper. Furthermore, on the basis of the MPO Corpus and HowNet Knowledge-base and sentiment analysis set, the feature words' semantic information is brought into the traditional vector space model to represent micro-blog documents. At the same time, the documents are classified by the subjects and sentiment intensity. Therefore, the experiment result indicates that the proposed method improves the efficiency and accuracy of the micro-blog content classification, the public opinion characteristics analysis and supervision in this paper. Thus, it provides a better technical support for content auditing and public opinion monitoring for micro-blog platform.

Performance Analysis of Unreliable Sensing for an Opportunistic Spectrum Sharing System

Abstract: Opportunistic spectrum sharing (OSS) is a promising technique to improve spectrum utilization using cognitive radios. Unreliable spectrum sensing by cognitive radios is inevitable in the OSS system. In this paper, we analyze the types of unreliable sensing and their impact on the system performance. The secondary users equipped with cognitive radios sense channels that are unused by the primary users and utilize the idle channels. An ongoing secondary user also detects when a primary user accesses its channel and then either moves to another idle channel or moves to a buffer if no idle channel is available. Unreliable spectrum sensing is modeled by false alarm and misdetection events for both initiating and ongoing secondary users. We solve the steady-state probability vector of the system and derive a set of performance metrics of interest. Numerical results are presented to highlight the analysis. The proposed modeling method can be used to evaluate the performance of future opportunistic spectrum sharing networks.

Applying Cluster Merging and Dynamic Routing Mechanisms to Extend the Lifetime of Wireless Sensor Networks

Abstract: In recent years, the applications of wireless sens or networks have increased steadily. Sensor nodes are often scattered outdoors and their energy consumption depends heavily on the area of coverage and network topology. Many studies were focused on saving the energy of sensor nodes to maintain their functionality. This work aims at extending the lifetime of a wirel ess sensor network by using cluster merging and dynamic routing mechanisms. Cluster merging can increase the number of sensor nodes in a cluster to balance its energy consumption; dynamic routing prevents the cluster heads from exhausting electric power by forwarding data through detoured routes. The simulation results show that c luster merging followed by dynamic routing is more efficient in ex tending network lifetime. The best combination of the above two mec hanisms is to set the threshold of the remaining energy to 90% for ap plying cluster merging and 10% for applying dynamic routing, which results in the lifetime about 9 times that of a wireless sensor ne twork without using the adaptive mechanisms.

New Trends of Radio over Fiber Communication Systems for Ultra High Transmission Capacity

Abstract: Radio-over-fiber (RoF) systems have been widely investigated due to such advantages of optical fiber as low loss, large bandwidth, and transparent characteristics for radio signal transmission. By utilizing RoF systems, various radio frequency (RF) signals including cellular services and wireless local area network (WLAN) signals can be efficiently distributed to densely populated areas or outdoor ranges. This paper investigates RoF transport systems that have the potential to offer large transmission capacity, significant mobility and flexibility, as well as economic advantage due to its broad bandwidth and low attenuation characteristics. The high performance of RoF communication systems are investigated against traditional optical communication systems using different coding formats over wide range of the affecting operating parameters. Moreover we have analyzed the transmission bit rates and products per channel based standard single mode fiber made of both silica-doped and plastic materials with using modified Shannon technique in addition to use different coding format such as non-return-to-zero (NRZ) code for ultra long haul transmission applications. We have taken into account the bit error rate (BER) for RoF systems with comparing it with traditional optical fiber communication systems as a proof for improvement of signal to noise ratio.

Message efficient global snapshot recording using a self stabilizing spanning tree in a MANET

Abstract: Distributed snapshots are a significant paradigm for distributed systems. These are applied for constructing checkpoint protocols, apart from investigating, testing, or proving properties in distributed executions such as deadlocks and termination. Though a number of snapshot algorithms exist for traditional distributed systems, they cannot be directly applied to mobile ad hoc networks due to the constraints of topology and hostile conditions in which the MANETs operate. The paper presents an algorithm for recording the global state of a clustered and multi-hop mobile ad hoc network. The proposed algorithm imposes a self stabilizing spanning tree upon the network topology to reduce the message overhead in the system due to the algorithm and to deal with the dynamic nature of MANETs. Moreover, the protocol handles concurrent snapshot initiation and does not require FIFO channels. The message complexity of snapshot recording is O(n-1) where n is the number of clusters in the system

Modeling and Analysis of Collision Avoidance MAC Protocol in Multi-Hop Wireless Ad-Hoc Network.

Abstract: The absence of centralized administration, multi -hop transmission, and the nature of wireless channels p ose many challenging research area in Mobile Ad hoc NETworks (MANETs). In this paper, a collision avoidance Medium Access Control (MAC) protocol was used for the modeling and analysis of multi-hop wireless ad hoc network, in which RTS/CTS/DATA/ACK handshake and Exponential Increase Exponential Decrease (EIED) back-off mechanism were adopted. A simple n-vertex undirected graph G(V, A) is used to model the topology of MANET while three-state Markov chain was used to model channel state and node state of MANET. Simulation results show that throughput increases with increase in persistent probability, sensing ra nge and length of a DATA frame. Also throughput has a peak value at some point of the persistent probability, sensing range and lengt h of a DATA frame, which is influenced by the number of nodes. In the other hand throughput increases along with the increase o f transmission range for some values, then it start decreasing wit h increase in transmission range. Furthermore throughput decreases with increase in the number of nodes and back-off time. In ord er to validate the proposed models, a performance comparison of the throughput of existing model with the throughput of the proposed model by considering persistent probability, sensing range, transmission range, length of DATA transmission and back-off time was carried out. The overall results show that the proposed mod el achieve better throughput than the existing model.

Design and Application of A New Hybrid Heuristic Algorithm for Flow Shop Scheduling

Abstract: a new heuristic algorithm was designed by combining with Johnson method, NEH method and characteristics of scheduling, and it was implemented on MATLAB. The efficiency of the new algorithm was tested through eight Car questions and two Hel questions of Benchmark problems, and the results revealed that the new heuristic algorithm was better than the other three heuristic algorithms. Further more; the application of this heuristic algorithm in the intelligent algorithm especially in the genetic algorithms (GA) was discussed. Two GAs were designed for Flow Shop question, and they had the same processes and the same parameters. The only difference is in the production of the initial population. One GA's initial population is optimized by the new heuristic algorithm, and the other whose initial population is randomly generated entirely. Finally, through the test of eight Car questions, it is demonstrated that the heuristic algorithm can indeed improve efficiency and quality of genetic algorithm because the heuristic algorithm can improve the initial population of GA.

Particle Swarm Optimization for Multi-constrained Routing in Telecommunication Networks

Abstract: By our analysis, the QoS routing is the optimization problem under the satisfaction of multiple QoS constraints. The Particles Swarm Optimization (PSO) is an optimization algorithm which has been applied to finding shortest path in the network. However, it might fall into local optimal solution, and is not able to solve the routing based on multiple constraints. To tackle this problem, we propose a new method of solving the multiple constraints routing. This paper firstly sets up a multi constrained QoS routing model and constructs the fitness value function by transforming the QoS constraints with a penalty function. Secondly, the iterative formulas of the original PSO are improved to tailor to non-continuous search space of the routing problem. Finally, the natural selection and mutation ideas of the Genetic Algorithm (GA) are applied to the PSO to improve the convergent performance. The simulation results show that the proposed GA-PSO algorithm can not only successfully solve the multi-constrained QoS routing problem, but also achieves a better effect in the success rate of the searching optimal path.

Modeling and Accomplishment of Loading-and- Unloading Equipment Optimum Allocation System at Bulk Terminal

Abstract: The configuration of port's loading-and- unloading equipment is an optimization problem, which endeavors to put limited handling equipment to each operating line to achieve the maximum overall production efficiency. We set up the T-stage decision-making model of loading-and-unloading line equipment configuration by using the method of Multi-stage Decision, and design the algorithm of the mathematical model. Research results in this paper lay the foundation for the development of loading-and-unloading equipment configuration system, and provide scientific basis for the decision of type selection and rational quantity of loading-and-unloading equipment.

A Fuzzy-based Routing Strategy for Multihop Cognitive Radio Networks

Abstract: Cognitive radio networks represent a new class of wireless networks where the channels are not permanently available, depending on the traffic activity of licensed users who have the priority to use these channels. We design a novel routing procedure for multihop cognitive radio networks composed of adequate metrics and a strategy to combine these metrics. The objective is then to increase channel availability when the routes are established. Two global metrics are defined. The stability metric evaluates the utilization efficiency of channels by capturing their sporadic availability to cognitive users. The predicted power metric estimates the spectrum capabilities for the on-going transmission without interrupting licensed users. We use fuzzy logic theory to compute and combine these metrics in order to make suitable routing decisions. Our procedure consists of two phases. In the first phase we compute the route to the destination, and in the second we examine the ability of this route to satisfy the required type of connection at the source. Numerical analysis and simulation results show that our procedure is able to find the route that goes through the nodes with better channel conditions. Fuzzy logic seems then to be an appropriate technique to decide the routes to establish in multihop cognitive radio networks.