Rajeev Tiwari

Cooperative Gateway Cache Invalidation Scheme for Internet-Based Vehicular Ad Hoc Networks

Internet-based vehicular ad hoc network is a fast growing technology with an aim to provide uninterrupted services such as regular safety alerts, entertainment, and resource sharing to the on board passengers even on-the-fly. On board passengers avail all these services even on-the-fly either in dense urban regions, or on highway using an Internet connection. Reduction in delay with an increase in the accuracy for accessing all these services from anywhere are the most challenging tasks to be performed in this environment. In literature, it has been found that caching the most relevant content at some of the intermediate sites may increase the overall performance of the network in this environment. In this direction, an important issue is to invalidate the cache when the original data items are updated and these data items are irrelevant for the end users. In this paper, we have been motivated and inspired from our earlier solution (Kumar and Lee in IEEE Syst J 8(4):1136–1144, 2014), in which we proposed a peer-to-peer cooperative caching scheme among the vehicles for urban scenario. But, in the current proposed scheme, we have enhanced our existing solution by proposing a Cooperative Gateway Cache Invalidation (CGCI) based upon cooperative cache invalidation technique. The designed scheme has the advantages of cooperation of Gateways in different regions along with the underlying location management scheme to reduce the number of broadcast operations, lesser Uplink requests, and query delay with an increase in the cache hit ratio. To test the effectiveness of the proposed scheme, we carried out extensive simulations by varying query arrival rate, object update rate, and cache size. Moreover, to evaluate the cost of query communication among the vehicles, an analytical model is also included in the proposed scheme. The results obtained confirm that the proposed scheme yields a reduction in the query delay with an increase in the cache hit ratio as compared to other state-of-the art existing schemes in literature.

A Novel Hybrid Approach for Web Caching

With the advancement of technology and development of many new applications now a days, the World Wide Web (WWW) suffers from scaling and reliability problems due to overloaded and congested proxy servers. Caching at local proxy servers helps, but cannot satisfy more than a third to half of requests, more requests are still sent to original origin servers. To address this issue, we propose a Hybrid Web Caching Algorithm (HWCA) for managing and searching in the cache of proxy servers. The algorithm uses Hierarchical Web Cache concepts along with static hierarchies with dynamic mechanism of proxy servers. Most of the requests are being satisfied through local proxy servers and very less requests are being fulfilled by remote origin servers. This mechanism keeps the congestion less on the network by using lesser bandwidth as most of the requests are satisfied from local sites. The proposed work is divided into three phases. The first phase is to characterize all the challenges in front of hybrid approach and all its viable study. In second phase, architecture is proposed for implementation of Hybrid Web Cache System. Third phase consists of the proposed algorithm for web caching. The performance of the proposed algorithm is evaluated using hit ratio and latency time of requests depending on varying cache sizes. The results obtained show that the proposed algorithm is effective in comparison to the existing techniques with respect to the above metrics.

Open Source Big Data Analytics Technique

In this mobile computing and business era, a huge amount of data is generated, which is Big Data. Such a large data becomes unmanageable and cannot be used for analytics using traditional methods. A large number of fields and sectors, ranging from economic and business activities, involve with Big Data problems. Big Data analytics is extremely valuable to make decisions for increasing productivity in businesses, which gives us a lot of opportunities to make great progresses in many fields. So, this paper discusses approaches and environments for carrying out analytics for Big Data applications. It revolves around important areas of analytics, Big Data, tools, and data base used. A comparative study is done and tabulated on parameters like Data Base used, real-time analytics, size, etc. Then on open source technology Kibana, Elastic search and JASON Query, a big data analytics experimental setup is done. Analytics is done in many dimensions like domain counts, percentile gross margins, sector-wise count, etc. Their drawn results are recorded and reported in form of graphs.

Dynamic Web caching: For robustness, low latency & disconnection handling

The Distributed Web caching system provides fast retrievals of web pages but still limited by the delays incurred by servers. As these systems are affected by low robustness due to highly congested servers. As in real time, servers get disconnected frequently providing tradeoff to service. Robust Distributed Web Caching (RDWC) handles robustness but fails to deal with the frequent disconnections. So in this paper, we discussed effective Distributed Web Caching (DWC), Distributed Web Caching with Clustering (DWCC) and Robust Distributed Web Caching techniques. Then a scheme is proposed and designed which can overcome frequent disconnections of proxy servers & more delays incurred in these schemes, it can send the replies back to clients in lesser time (by factor n- Best Case). Clustering of Proxy Servers is used with dynamic allocation of requests to less congested servers to achieve load balancing and robustness. Then a comparison of our Scheme is done with these and results are given in comparative table.

Impact of Information Technology and Sedentary Lifestyle on Occupational Health

The present paper shows the effect of high information technology in different working sections with their different occupational problems. All data of present study was selected from teaching and non-teaching sections where computer work is mandatory to complete their work. All samples have been selected from different areas of Dehradun, Uttarakhand. Personal interaction in survey method was applied for present study. Questionnaire tool was also used for the present study. The males sampled for the current study were in the age group 30–50 years. Total 289 samples were selected, and out of that 237 were detected with occupational health discomfort and the rest were normal. The present study shows that sedentary lifestyle and work involving documentation results in high incidence of back pain with high rate of blood pressure. Central obesity was common in maximum number of samples because of lack of physical work.

Optimization of Data Centres for Heat Management

Servers are backbone of our digital age. In recent times, operation and managing operation system has become a lot easier. But still server management comes with its own set of challenges like cost constraints, network latency, environment. The biggest obstacle in managing the server is heat management, because it indirectly affects other factors like operation cost, environmental impact and many more. There could be many ways to manage heat on the server, but one of the most effective ways could be to optimize the infrastructure of data centre. In this literature, we try to explore various fractural arrangement and practices to optimize data centre for heat management.

Analysis of Mahout Big Data Clustering Algorithms

Log data generated from any of the source or communicating devices is huge; to analyze such data we need to categorize them in some clusters. Depending upon clusters, data analytics can be done. Enabling the analytics in data helps in identification of business patterns and behavior of customers. Analyzing such big data is a major task, so distributed computing is used in Hadoop platform and machine learning library Mahout is used. Weighting technique TF-IDF is used for vectorization of data, and clusters are formed using clustering algorithms for doing analysis. Clustering algorithms K-mean, fuzzy K-Mean, LDA, and spectral clustering in Mahout are used and analyzed on basis of execution time, number of clusters, static or dynamic cluster creation.

Dynamic cache invalidation technique in mobile environments

Due to exponential requests of users for accessing Internet wireless services, longer delays can incur in full filling requests. So optimizations for delay is required. One such method is using cache and storing frequently accessed pages in local cache. Consistency in cache and server data becomes a major issue. As if cache is not valid then whole optimization will be lost. Many researches have strong consistency mechanism which incurs longer delays in query responses. In this paper, we explored some of vital cache invalidation techniques for mobile devices. Focused on advantages and disadvantages of each technique and then found few important parameters for their performance comparison like state full, stateless, IR based, Time-stamp based or not, congestion, query delay and Round Trip Time(RTT) etc. Then we conceptually evaluated the performance of cache invalidation schemes which indicates that the schemes with smaller and dynamic IRs can remarkably reduce the query delay and can utilize the bandwidth more efficiently.

Performance comparison of cache invalidation techniques in mobile computing environment

Advancement in evolution of Internet technologies like 3G, 4G, and 5G, there is a need of good quality of service (QoS) for such wireless networks. Faster responses are required for various queries raised by mobile terminals (MTs) from any mobile computing environment. There has been many research works proposed in the past to address the QoS issue by using an Invalidation Report (IR)-based cache management schemes. In all such cases, IRs become unmanageable due to the poor utilization of available bandwidth and larger size of IRs. Broadcast times are fixed and longer due to which IR looses its effectiveness and hit ratio degrades, So, to address these issues, in this paper, we have simulated cache invalidation techniques scenario on NS2.35, peer cache invalidation techniques like Time Stamping and Update Invalidation Report based techniques are simulated and tested to show performance on basis of various parameters like Hit Ratio, Query Delay by varying cache update interval and cache size. At the end we have also suggested the future directions for such techniques.

Detecting community structure based on traffic at node in networks

In the study of networks, such as complex network, social network or biological network; number of different characteristics of many nodes are found common. These characteristics includes small-world property, clustering and community structure, among others. In the context of networks, community structure refers to occurrence of groups of nodes in a network that are more densely connected internally, then with the rest of network. This heterogeneity of connection suggests that network has certain natural division within it. Being able to identify their sub-structure within the network can provide inside into how network function and topology affects each others.