Sabariah Baharun

ReviewAuthentication in mobile cloud computing: A survey

Mobile cloud computing (MCC) is the state-of-the-art mobile distributed computing model that incorporates multitude of heterogeneous cloud-based resources to augment computational capabilities of the plethora of resource-constraint mobile devices. In MCC, execution time and energy consumption are significantly improved by transferring execution of resource-intensive tasks such as image processing, 3D rendering, and voice recognition from the hosting mobile to the cloud-based resources. However, accessing and exploiting remote cloud-based resources is associated with numerous security and privacy implications, including user authentication and authorization. User authentication in MCC is a critical requirement in securing cloud-based computations and communications. Despite its critical role, there is a gap for a comprehensive study of the authentication approaches in MCC which can provide a deep insight into the state-of-the-art research. This paper presents a comprehensive study of authentication methods in MCC to describe MCC authentication and compare it with that of cloud computing. The taxonomy of the state-of-the-art authentication methods is devised and the most credible efforts are critically reviewed. Moreover, we present a comparison of the state-of-the-art MCC authentication methods considering five evaluation metrics. The results suggest the need for futuristic authentication methods that are designed based on capabilities and limitations of MCC environment. Finally, the design factors deemed could lead to effective authentication mechanisms are presented, and open challenges are highlighted based on the weaknesses and strengths of existing authentication methods.

Cloud Cognitive Authenticator (CCA): A public cloud computing authentication mechanism

The long awaited Cloud computing concept is a reality now due to the advancement and transformation of computer generations. However, the implementation of this concept as a technology is still at infancy stage due to several issues such as policy, standards, users, security, etc. This paper features the basic concepts of cloud computing, security issues and proposes an integrated authentication mechanism called the Cloud Cognitive Authenticator (CCA). CCA is an API proposed for the cloud environment integrating bio-signals, one round Zero Knowledge Protocol (ZKP) for authentication and Rijndael algorithm in Advance Encryption Standard (AES). CCA is proposed to enhance the security in public cloud through four procedures providing two levels of authentication as well as encrypting/decrypting the user id. The novelty of CCA is that it uses Electro Dermal Responses (EDR) for the first level authentication. Furthermore, the proposed encryption in CCA provides concrete cryptography. Finally, this paper concludes with the future direction of this study.

Spectrum aware cluster-based architecture for cognitive radio ad-hoc networks

To encounter the mounting necessity of radio spectrum, proper utilization of the radio spectrum is must. Cognitive radio practices an open spectrum allocation technique to make efficient utilization of the wireless radio spectrum and reduces the bottleneck on the frequency bands. A robust architecture with suitable communication protocol is a precondition in the deployment of cognitive radio networks. A novel cluster-based architecture for an ad-hoc cognitive radio network is proposed in this paper, where the spatial variations of spectrum opportunities are considered for clustering. Our cluster formation is defined as a maximum edge biclique problem. Each cluster consists with a set of free common channels, which benefits smooth shift between control channels. A set of cognitive radio nodes are grouped into the same cluster if they sense similar free channels and are within the communication range of the leader node called cluster head. The selection of cluster head is based on a parameter called Cluster Head Determination Factor (CHDF). Considering the re-clustering issue for mobile nodes, we also introduce the concept of secondary cluster-head. The secondary cluster-head takes charge of a cluster whenever a cluster-head moves out from the cluster. Proposed clusters adapt themselves dynamically with respect to spectrum availability, and the high mobility of the nodes. Finally, we simulate the proposed architecture to evaluate the performance of our method.

CoAd: A cluster based adhoc cognitive radio networks architecture with broadcasting protocol

Considering the mounting demand of radio frequencies, proper utilization of the spectrum is very essential. Cognitive radio, which uses an open spectrum allocation technique, can solve this spectrum congestion problem. Effective deployment of cognitive radio networks highly depends on a robust architecture with appropriate communication protocols. Considering the limitations of recently developed cognitive radio network architectures and associated broadcasting protocols, a dynamic cluster-based simple architecture is proposed for Ad-hoc cognitive radio network. For effective routing and load balancing, proposed architecture is dividing Ad-hoc architecture into clusters. The paper also introduces time slotted based broadcasting protocol for the proposed clustered architecture. Simulation results show the clustering efficiency of the proposed architecture.

Multi-nodes joining for dynamic cluster-based Wireless Sensor Network

The state of the art of Wireless Sensor Networks (WSNs) has enabled attainment of complicated and challenging applications such as healthcare, traffic control, habitat monitoring, etc.. For the last few years, clustering in WSNs has gained more consideration because of the improved ability of sensor nodes to conserve energy. In a dynamic WSN, clustering consists of two important stages: cluster formation and cluster maintenance. A cluster is formed once a node or a group of nodes join an existing cluster-based network and cluster maintenance is executed to handle node(s) leaving or even re-joining. In this paper, we investigate cluster formation problems for a dynamic cluster-based WSN. Current dynamic cluster-based WSN supports only single nodes joining and/or leaving. We enhance the cluster-based structure by proposing multi-nodes-joining algorithms. We show that the time complexity of the proposed algorithm is expected O(|Q| + |R|) rounds, where R is the set of new nodes wish to join and Q is the set of neighboring nodes of set of new nodes R. We also show some simulation results for the proposed algorithm.

Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey

New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR) and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC) protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN). First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective.

PM10 black carbon and ionic species concentration of urban atmosphere in Makassar of South Sulawesi Province, Indonesia

Abstract This paper presents a study on black carbon and ionic species concentrations in PM 10 , sampled from the urban area of Makassar in the Province of South Sulawesi, Indonesia. The samples were collected on a weekly basis within a period of one year from February 2012 to January 2013. Results showed that the mean concentration of PM 10 black carbon was 2.01xa0±xa00.93xa0μg/m 3 , while ionic species concentrations were found in descending order; SO 4 2− >NO 3 − >Cl − >NH 4 + , with mean concentrations of 1.44xa0±xa01.04xa0μg/m 3 , 1.11xa0±xa01.06xa0μg/m 3 , 0.87xa0±xa00.91xa0μg/m 3 , 0.49xa0±xa00.64xa0μg/m 3 , respectively. Black carbon concentration was higher during the dry months, which may be attributed to uncontrolled biomass burning during hot and dry weather conditions. Similarly, SO 4 2− and NH 4 + concentrations were higher during the dry month seasons. On the contrary, Cl − concentration was higher during the wet months, influenced by the marine environment surrounding the area.

Energy-efficient and mobility-aware MAC protocol for wireless sensor networks

Wireless sensor networks (WSNs) have restricted use by both academic and industrial societies for a while. This is due to the limited electrical and computational power of a typical sensor node. By moving toward emergency and healthcare related applications such as the disaster response, mobility has become an important feature of WSNs. Having the mobile nodes in a WSNs causes new and even more challenging technical difficulties for its designers. The existing technologies should be revised in order to comply to the new form of applications. In this paper, an enhanced mobility-aware extension to T-MAC, as one of the popular medium access control protocols in WSNs is proposed. The simulation-based experiments show that the proposed method significantly increases the throughput and packet delivery ratio of T-MAC in exchange for a small increase in power consumption.

Anisotropic contrast diffusion enhancement using variance for wireless capsule endoscopy images

Wireless capsule endoscopy (WCE) is useful to detect abnormal area in human digestive tract. However, many WCE images have low quality such as rather dark and noisy. Smoothing is an effective way to removing noise and to enhance the images. However, smoothing has a drawback since it can damage the image features. Studies had shown that anisotropic diffusion is a technique used to reduce image noise without removing image features such as edges, lines, textures or other details. These significant parts of the image content are important for the interpretation of the image. To further enhance WCE images, contrast diffusion is used by using Hessian matrix. The original method proposed by B. Li has weakness where it degrades the quality of image when number of iteration goes up. To overcome this problem, standard variance and Gaussian filter is employed in our proposed scheme. Experimental and comparative results of the proposed method are presented in this paper.

Comments and improvements of “HOTA: Handover optimized ticket-based authentication in network-based mobility management”

Nowadays, various mobile devices are being an inseparable part of our normal life. Mobile users tend to be connected to the Internet seamlessly, which is provided by mobility management protocols. One of the latest mobility management protocol is Proxy Mobile IPv6 (PMIPv6), which is a network-based protocol. Authentication mechanism as a critical security procedure is not specified in PMIPv6, hence various authentication methods have been proposed. Lee and Bonin proposed a ticket-based authentication scheme for PMIPv6, which is called HOTA in 2013. Even though, HOTA offers some security protection mechanisms, but is vulnerable to DoS attack. Furthermore, we show other existing drawbacks to the scheme such as vulnerability against de-synchronization attack and Session Hijacking attack. In this paper, we propose an enhancement method to mitigate these security drawbacks. Finally, security and performance of the proposed method are analyzed and compared to HOTA method.