Performance evaluation of seed values and pause times over high speed Wireless Campus Network in IEEE802.11e

IEEE802.11e standard assures to provide QoS using service differentiation mechanism over WLAN. The Enhanced Distributed Channel Access (EDCA) mechanism employs to differentiate the multimedia traffic based on assigned priorities and allows accessing the channel.Only one category of traffic permits access to the channel at a time to avoid traffic collision over the network. In EDCA, the back-off window algorithm generates back-off window size randomly during traffic transmission through the channel to prevent other categories of traffic to access the channel. Due to this randomness of back-off window algorithm to provide probabilistic QoS to satisfy the multimedia traffic through the network, the random mobility model can reduce the network performance. In this paper, we analyze the proposed network performance based on the variation of randomness using different seed values according to different pause time and evaluate the network performance using various performance metrics in IEEE802.11e

The impact of randomness on high speed wireless campus network in IEEE802.11e

The enhancement of channel access mechanism assures to provide Quality of Service (QoS) using the service differentiation mechanism over WLAN in IEEE802.11e. The service differentiation scheme is used in the Enhanced Distributed Channel Access (EDCA) MAC layer protocol and this protocol is used the random back-off window algorithm to provide QoS for the real time multimedia applications. However, the back-off window mechanism ensures QoS to satisfy multimedia traffic but it only the probabilistic QoS due to the random nature of the algorithm. As like as the randomness of the mobility models that can be reduced the network performance. In this paper, we analyze the proposed network performance based on the variation of randomness using different seed values and evaluate the network performance using various performance metrics in IEEE802.11e

Authenticating sensitive diacritical texts using residual, data representation and pattern matching methods / Saqib Iqbal Hakak

Diacritics play an important role in interpreting the meaning of a sentence through the proper pronunciation. Any text that needs diacritics is sensitive as any disarrangement of diacritics (intentional or unintentional) will result in complete misinterpretation of the text. There are different diacritics like punctuation symbols, extended letters (e.g. kashidas) and other symbols, that can be easily tampered to alter the original meaning of the text. There are limited studies focused on the authentication of such sensitive diacritical content (SDC). Most of the studies have removed the diacritics for authentication making the process questionable. Besides, the proliferation of such a sensitive content in different languages and formats on the internet has further exaggerated the issue of authentication involving search and retrieval phases. To address the mentioned issues, this thesis presents the different methods to authenticate the SDC with the aim to improve the searching and retrieval phases. The first method is based on the residual approach that authenticates any two similar sample texts written in different styles using one common database. It minimizes the overhead associated with maintaining the multiple databases. The objective is achieved using logical operations and the character segmentation. The second method is based on the representation of the diacritical text within the database to improve the retrieval performance for authentication of a single sentence (verse). The objective is achieved by creating individual nodes based on the total number of characters and placing each diacritical verse within its respective node. The last method is based on the pattern matching approach, where given multiple pattern input is authenticated from a given text. The purpose of exploring pattern matching approach is to authenticate multiple diacritical verses with improved time and space efficiency. The proposed method works by splitting the given pattern into two halves and searching for the respective halves. The searching of halves is achieved through two different algorithms based on the split approach and the parallel approach respectively. To show the practicality of the proposed methods, they are tested on sensitive diacritical text, which includes the Arabic Digital Holy Quran (DHQ). The reason for selecting the DHQ for evaluation purposes is its availability in different styles like uthmani and plain Arabic style that makes evaluation possible based on our first method. The second reason is the complexity of diacritics within DHQ and encoding scheme that decreases the authentication performance due to inefficient data representation and search/retrieval strategies. The mentioned reason made the evaluation of the second proposed method feasible and practical. Finally, for evaluating the pattern matching based approach, different sensitive texts including Arabic, French. Italian, English and Chinese were taken. The findings show that the first method manages to convert Uthmani and Plain Quranic verses into one common style with an accuracy of about 87 %. Similarly, the second method manages to authenticate single DHQ verse with the improvement in search time by approximately 70 % over the existing methods. Finally, the final method successfully authenticates multiple verses of different sensitive diacritical texts with improved computational time and memory consumption

MARKCLOUD - Software for data confidentiality and security in cloud computing environments

Cloud computing is one of the most recently emerged technology which offers resource on demand facility. Cloud computing is an information technology deployment model that involves entrusting data to information systems managed by external parties on remote servers or 1Cin the cloud. 1D In cloud, resources, in terms of infrastructure, applications and data are deployed via the internet as a distributed service by service provider, which make use of applications without installations. This technology allows much more efficient computation by centralizing storage, memory, and processing as well as band width. However, despite the surge in activity and interest, there are significant, persistent concerns about confidentiality and security of data in cloud computing that prevented business organizations from fully accepting cloud platforms. In this paper, cloud computing security issues have been addressed. In addition, and equally importantly, an algorithm has been proposed that can be used between service providers and data owners to safeguard multi-way authentications and tighten access control for sensitive data in both public and private cloud

Impact of packet size and node mobility pause time on average end to end delay and Jitter in MANET's

Mobile ad-hoc network (MANET) is a self-configuring infrastructure less network of mobile devices connected by Wireless and each node or mobile device is independent to move in any desired direction and thus link goes on changing from one node to another. In MANET's, routing is considered as one of the most difficult and challenging task and due to that reason, most of the studies have focused on comparing protocols with each other under varying network conditions. But to the best of our knowledge no one has studied effect of different factors on network performance indicators like throughput, Jitter and so on, as how much influence a particular factor or group of factors is having on network performance indicators itself. Thus, in this paper effect of three key factors i.e. Routing protocol, packet size and Node Mobility Pause time is evaluated on the key network performance metrics i.e. Average Delay and Average Jitter, as these parameters are crucial for network performance and directly affects the buffering requirements for all video devices and downstream network. Also excess value of Delay and jitter can lead to many problems ranging from lip-synchronization problem to the loss of packets because of buffer overflow or underflow

Effect of mobility model and packet size on throughput in MANET's

Ad-hoc mobile/802.11 networks are those networks which has got no fixed topology due to the movement of end nodes. Each node within mobile adhoc network can act both host as well as router. For these mobile nodes to be properly functional and operational, routing protocol is required. And for this very purpose, studies have been going on, which protocol is better. Little emphasis has been laid on network Performance indicators as which factors are most important for a specific Performance indicator. To the best of our knowledge no one has studied effect of different factors on network performance indicators like throughput, Delay and so on, as how much influence a particular factor or group of factors is having on network performance indicators itself Thus, in this paper, effect of routing protocol, packet size and node mobility pause time have been evaluated against one of the most important network performance metric i.e. Throughput

Wandel der Niederschlagsverhältnisse im Lee des Harzes

Fabig, Ilka: Changing precipitation leeward of the Harz Mts. - Indicators of a regional climate change. – Hercynia N.F. 40 (2007): 33-39.The global average surface temperature has increased during the 20th century. Subsequent effects of climate change vary regionally and seasonal and moved the consideration of regional impacts to the center of interest. Precipitation is a highly variable climate element in time and space with serious economic and ecological weight. The “Mitteldeutsches Trockengebiet” with its already tense regional water regime faces radical future changes. The aims of the study, a detailed stock-taking of rainfall data with regard to their spatial and temporal pattern was accomplished with a statistical evaluation of long-term precipitation data. The essential result of the study is the detection of an annual change in precipitation, which is characterized by more humid conditions in winter and drier summers. The shorter observation periods show different trends of precipitation. In summary it can be ascertained, that particularily for the investigation area, precipitation is the most limiting climate factor.Fabig, Ilka: Changing precipitation leeward of the Harz Mts. - Indicators of a regional climate change. – Hercynia N.F. 40 (2007): 33-39.The global average surface temperature has increased during the 20th century. Subsequent effects of climate change vary regionally and seasonal and moved the consideration of regional impacts to the center of interest. Precipitation is a highly variable climate element in time and space with serious economic and ecological weight. The “Mitteldeutsches Trockengebiet” with its already tense regional water regime faces radical future changes. The aims of the study, a detailed stock-taking of rainfall data with regard to their spatial and temporal pattern was accomplished with a statistical evaluation of long-term precipitation data. The essential result of the study is the detection of an annual change in precipitation, which is characterized by more humid conditions in winter and drier summers. The shorter observation periods show different trends of precipitation. In summary it can be ascertained, that particularily for the investigation area, precipitation is the most limiting climate factor

Performance analysis of MAC layer scheduling schemes for IMM applications over high speed wireless campus network in IEEE802.11e

In IMM traffic, while establishing a voice or video conversation, the sender and the receiver (the participants) should be mutually benefited by ensuring QoS like minimum data loss, sharing sufficient bandwidth and achieving high throughput over the WCN. To improve the network performance, scheduling mechanism is a challenging issue in the transmission of IMM traffic and it still needs to be solved over WCN. This paper aims to employ three different MAC layer scheduling mechanisms such as FIFO, RED and WRED for analysing the performance over the network, based on variation of traffic load in IEEE802.11e, and to evaluate the proposed schedulers’ performance using different performance metrics in WCN. Here, the traffic load is varied by increasing the packet size and the traffic arrival rate, respectively. In order to analyse the network performance, the simulation has been done in QualNET 5.1 simulator. In the simulator, the mobility model is chosen as ‘Random Waypoint’ to change the node position randomly and the application as CBR. Simulation results show that increasing the packet size enables RED and WRED schedulers to perform better than FIFO in terms of all the performance metrics. On the other hand, increasing the traffic arrival rate helps to enhance the performance of the FIFO scheduler compared to the FIFO scheduling mechanism in the previous case. It is conclusive through the performance analyses that all three schedulers perform comparatively better when the traffic arrival rate is increased compared to increasing the packet size

Cloud-assisted gamification for education and learning – Recent advances and challenges

Gamification has gained considerable interest in education circles due to its capability of enhancing the learning process among students. In the future, it is expected that gamification will overtake the traditional way of learning resulting in issues such as scalability, upgradation of learning modules. To address these issues, merging gamification with cloud computing seems a viable solution. However, the employability of gamification through cloud computing is still in its infant stage. Hence, this article investigates the applicability of gamification through cloud computing and presents a comprehensive survey of state-of-the-art gamification in education and learning. We also identify the subject areas that can be gamified and taught using the cloud service. The critical elements and minimum requirements necessary to gamify education are also identified. Moreover, a specific cloud-assisted gamification architecture is proposed and discussed together with its possible applications. The article is concluded with the research challenges and suggestions for future work

Application of UWB wireless MIMO connectivity inside modern aircraft

Monitoring a large number of interacting sensors, actuators and controllers in sensitive locations simultaneously, requires efficient and fast network. Sophisticated computer controlled systems in modern aircrafts have become a necessity. Wired connectivity can be both awkward and hazardous. In this paper we propose wireless connectivity based on Impulse-Radio Ultra Wideband (IR-UWB) system. It is a promising technology for the exchange of high data rates in a limited space. It acts like a Personal Local Area Network (PLAN) suitable for limited space within an aircraft. The proposed scheme utilizes the novel pulse generator developed in these laboratories. The pulse shapes comply with the FCC regulations regarding power levels and spectral mask limitations. It mitigates interference effects with narrowband systems. The proposed scheme has been analyzed theoretically and implemented practically giving sound results. It has so far proved to be an excellent short-range communication technology in terms of cost, speed, power consumption and capacity. A practical system is designed and built, which is capable of operating in the Gbps range. The proposal is anticipated to open possibilities for further applications such as ships, control towers operating theaters, and any other application where a large number of peripherals are in interaction simultaneously. The UWB pulse generator produces pulses, which are portions of simple monocycle sine wave shapes in the GHz range. Results obtained through simulation and theoretical analysis show excellent and constant agreement with results obtained by experimental measurements