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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Transactions on Combinatorics
- نوع مقاله: Journal Article
- کلمات کلیدی: diameter,root,integral graph
- چکیده:
- چکیده انگلیسی: In this paper, we construct a new class of integral bipartite graphs (not necessarily trees) with large even diameters. In fact, for every finite set $A$ of positive integers of size $k$ we construct an integral bipartite graph $G$ of diameter $2k$ such that the set of positive eigenvalues of $G$ is exactly $A$. This class of integral bipartite graphs has never found before.
- انتشار مقاله: 15-11-1394
- نویسندگان: Alireza Fiuj Laali,Hamid Haj Seyyed Javadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Computing and Security
- نوع مقاله: Journal Article
- کلمات کلیدی: Key management,Ad Hoc Network,Key Revocation,Accusation Packet
- چکیده:
- چکیده انگلیسی: Considering the dynamic and wireless topology of the mobile ad hoc networks (MANETs), the implementation of security in such networks is an important problem. Key revocation is a solution for this challenge which prevents the continuous presence of the attacker in the network and disclosure of confidential information. In some suggested key revocation protocols such as Liu et al.'s scheme, each node monitors the network and will send an accusation packet to the authority center if it receives a suspicious behavior from the neighboring nodes.Then, the authority center decides to revoke the key of the accused node based on the number of received accusations. Due to the fact that the participation of the nodes is time consuming, the threshold for the number of accusations is an important factor for key revocation procedure. In this paper, a stochastic model is presented to determine the optimal threshold for the number of accusations and the appropriate time for decision making in the key revocation protocol. Based on some assumptions, the threshold parameter is used in key revocation scheme of Liu et al. and results are evaluated by simulation. Simulation results show that the proposed threshold for the number of accusation packets enhances the efficiency and effectiveness of the key revocation protocol for MANET.
- انتشار مقاله: 19-05-1393
- نویسندگان: Maryam Zarezadeh,Mohammad Ali Doostari,Seyyed Hamid Haj Seyyed Javadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Communication Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Security,Wireless sensor networks,Key pre-distribution,Combinatorial design theory
- چکیده:
- چکیده انگلیسی: The establishing of a pairwise key between two nodes for encryption in a wireless sensor network is a challenging issue. To do this, we propose a new deterministic key pre-distribution scheme which has modified the multiple key space scheme (MKSS). In the MKSS, the authors define two random parameters to make better resilience than existing schemes. Instead of a random selection of these parameters, our proposal provides a combinatorial framework by substituting appropriate parameters to satisfy certain properties. We show that the proposed scheme enhances storage memory and improves performance or security by carefully choosing a combinatorial design. In addition, we propose a new key agreement mechanism by using derivative operation on univariate polynomials to aim a desired computational overhead. In this case, the computational overhead of our approach lower than the general case of the MKSS’s. If we choose the primitive element in our general formula as the special case of the MKSS, this new process has the same computational overhead as the MKSS.
- انتشار مقاله: 17-12-1395
- نویسندگان: Ibrahim Qasemzadeh Kolagar,Hamid Haj Seyyed Javadi,Shahriar Bijani
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Advances in Computer Engineering and Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Fuzzy system,distribution key,dynamic wireless sensor networks,pre-distribution key,head cluster selection
- چکیده:
- چکیده انگلیسی: A sensor node is composed of different parts including processing units, sensor, transmitter, receiver, and security unit. There are many nodes in a sensor unit. These networks can be used for military, industrial, medicine, environmental, house, and many other applications. These nodes may be established in the lands of enemies to monitor the relations. Hence, it is important to consider conservation of communications, declaration, and key removal. The locations of nodes are not usually defined in the networks. When a secure connection is required they can be used by symmetrical or asymmetrical encodings. A node can just make secure connection, if they are in same radio range or have a common key. In dynamic wireless sensor networks compared with static networks the sensors are moveable and can be added or removed. This research makes an attempt to investigate the challenges of key management for encoding. It also tries to solve other remained problems in this field. Therefore, distribution and key management schemes supplying security and operational requirements of sensor networks are examined in fuzzy clustering and suitable protocol for key management.
- انتشار مقاله: 05-02-1395
- نویسندگان: Asghar Dolatabadi,Hamid Haj Seyyed Javadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Advances in Computer Engineering and Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Wireless sensor networks,Key pre-distribution,Symmetric BIBD
- چکیده:
- چکیده انگلیسی: Key distribution is an important problem in wireless sensor networks where sensor nodes
are randomly scattered in adversarial environments.
Due to the random deployment of sensors, a list of keys must be pre-distributed to each sensor node before deployment. To establish a secure communication, two nodes must share common key from their key-rings. Otherwise, they can find a key- path in which ensures that either two neighboring nodes have a key in common from source to destination. Com-
binatorial designs are powerful mathematical tools with comprehensive and simple structures. Recently, many researchers have used combinatorial designs as key pre-distribution scheme in wireless sensor networks. In this paper we consider a hybrid key pre-distribution scheme based on Balanced Incomplete Block Design. We consider a new approach for choosing key-rings in the hybrid symmetric design to improve the connectivity and resilience. Performance and security properties of the proposed scheme are studied both analytically and computationally. The
obtained results show that our scheme provides better resilience than symmetric design.- انتشار مقاله: 28-06-1394
- نویسندگان: Hamid Haj Seyyed Javadi,Mohaddese Anzani
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Mathematical Finance and Application
- نوع مقاله: Journal Article
- کلمات کلیدی: Data envelopment analysis,Banking industry,Financial Cloud Computing,Dynamic Network model,QoS Attributes
- چکیده:
- چکیده انگلیسی: Nowadays, the great benefits of cloud computing have dramatically increased the number of e-banking users. Hence, the competition in the banking industry has boosted and managers need to evaluate their branches on a regular basis. To this end, this study aims to evaluate cloud-based banking systems based on the Quality of Service (QoS) attributes using the Dynamic Network Data Envelopment Analysis (DNDEA) model. The main advantage of this research is that the efficiency of cloud-based bank branches can be estimated more realistically according to their internal structure over a specific time span. To conduct the experiment, 40 bank branches in Iran are analyzed by considering between-period and divisional interactions during 2018-2019. A cloud-based bank branch is conceptualized as a set of three inter-connected divisions including capabilities, intermediate process, and profitabilities. Some outputs of sub-DMUs 2 and 3 are treated as desirable and undesirable carry-overs between consecutive periods. In addition, the cost items and QoS attributes are considered as the inputs and outputs of divisions, respectively. The results indicate that 28 bank branches were efficient and all of the inefficiencies fall in divisions 1 and 3. Moreover, the number of efficient branches has been reduced from 2018 to 2019.
- انتشار مقاله: 09-02-1399
- نویسندگان: Alireza Poordavoodi,Mohammad Reza Moazami Goudarzi,Hamid Haj Seyyed Javadi,Amir Masoud Rahmani
- مشاهده