We introduce a novel algorithm called IGOD to identify the geolocation of the cloud data center which is hosting the data of a mobile user. IGOD efficiently geo locate any target data center as accurately as possible and is highly cost-effective. It provides audit control and assurance against the cloud storage providers who may relocate mobile customer's data. We use Planet Lab for our data collection. We compared our approach to the earlier approaches that used Ping delay to predict the geolocation of a target. We claim that IGOD is highly cost-effective.

Mobile communication has become an essential information exchange platform for today's enterprise and government organizations. Their employees extensively use mobile devices to support their job activities while they are on the move. Organizations need to secure mobile devices as they secure wired devices. Organizations while securing mobile devices, also have to secure themselves from mobile devices as these devices are easily prone to attacks. We introduce the idea of "location-attack protection" where traffic from high cyber-crime locations (country, state, city, etc.) can be completely blocked. The main objective of this paper is to build a Flexible Perimeter Protection Framework (FPPF) that provides perimeter protection policies that react to dynamic changes, which is quite frequent in mobile setups and respect organizational objectives such as preferential treatment, yet enforce overall security objectives of organizations.

In this paper we evaluate the merit of Brooks-Iyengar distributed sensing algorithm and highlight its impact on cost-effective processing of real-time sensor data stream. We discover that it has a long-lasting impact, not only on sensor networks, but also on computer operating systems. We believe that as we learn more about the usefulness of this algorithm, it will become an essential component of system that use sensors in some form.

We present two new key generation schemes for secure communication between a pair of mobile nodes (cell phones). Unlike existing algorithms, our scheme does not (a) store a key chain in the memory from a universal key space, (b) use key broadcast, (c) distribute selected keys to the network nodes, and (d) use database of keys for selecting keys for communication. Rather, the pair of nodes that want to communicate securely generate identical keys independently with the help of a head node. We show the behavior of these schemes through a simple analytical model.

Moving objects share space for managing their mobility. For example, vehicles share roads, airplanes and UAVs share the sky or under-water space, etc. The problem then can be stated as “how moving objects can self-synchronize over the use of common resource (space, intersections, etc.) to maintain a conflict-free movement without the aid of a third party?” In this paper we describe our self-synchronization scheme for traffic movement through intersections. We claim that our scheme will be able to introduce fairness, reduce or eliminate the accidents (conflicts), and significantly reduce the cost of traffic management by eliminating the traffic lights that have very little intelligent and other traffic signs such as stop, give way, etc. Our scheme not only implements traffic-light logic but also human drivers' discretion to some extent. We present a simulation model to illustrate the working of our mechanism using simulated mobile cars.

Summary form only given. Data caching is an effective way of improving system performance. This is especially crucial in mobile databases because of the limited bandwidth and slower communication speed of wireless channels. In this paper we present a data caching algorithm, referred to as HDC (hot data caching), and compare its performance with LRU (least recently used) cache replacement scheme through simulation.

Recent advances in mobile computing and wireless communication have enabled the deployment of broadcast based information systems such as, wireless internet, traffic information, etc. The users and research community have recognized its potential for meeting the growing information demands of the future. At present existing systems are mainly pull-based (on-demand) and their performance highly depends on the broadcast schedule they use. Previous studies in on-demand scheduling have focused mainly on single item requests to keep the investigation simple. However, scheduling algorithms for single item request are unable to manage efficiently multi-item requests which are becoming more common. In addition to this these more and more requests are becoming transactional in nature. In this paper we take into consideration these requirements and study scheduling problems arising in on-demand broadcast environment and propose an efficient algorithm. We report its performance and demonstrate that our algorithm successfully manage multi-item simple and transactional requests and significantly reduces the wait time, tuning time and avoids transaction aborts.

We propose an concurrency control mechanism (CCM) for mobile database systems (MDS) that ensures epsilon serializability and report its performance.

Together with wireless communication technologies, portable computers and hand-held devices provide a pervasive base for mobile computing. Mobile computing involves mobility of users, hardware, software and data. In addition to advances in communications and hardware, mobile and wireless access requires innovative theories and paradigms in data management and new data engineering techniques in order to cope with the inherent limitations of the mobile environment while satisfying the users’ new expectations and needs. This seminar aims at covering such data engineering aspects along two dimensions: (a) the wireless network perspective, and (b) the information processing perspective. Thus, this seminar provides a good overview of current methods and practices in building mobile information systems, examine mobile and wireless infrastructures and discuss challenging research problems in all aspects of mobile information processing.

Semantic caching is very attractive for use in distributed systems due to the reduced network traffic and the improved response time. It is particularly efficient for a mobile computing environment, where the bandwidth of wireless links is a major performance bottleneck. Previous work either does not provide a formal semantic caching model, or lacks efficient query processing strategies. This paper extends the existing research in three ways: formal definitions associated with semantic caching are presented, query processing strategies are investigated and, finally, the performance of the semantic cache model is examined through a detailed simulation study.

Mobile IP is an Internet protocol designed to support host mobility. It provides the host the ability to stay connected to the Internet regardless of its location. This paper presents a modified Mobile IP protocol, (Dynamic Mobile (IP-DM-IP)). DM-IP eliminates triangular routing, which exists in current Mobile IP and it can be easily implemented in the existing wireless infrastructure. In DM-IP the packets can be sent directly from the communicating host to the mobile node bypassing the "home agent". We also present a TCP protocol (Nice TCP (N-TCP)), which considers the packet losses due to mobility and wireless errors. The congestion control criteria are modified so that by default the TCP does not need to invoke congestion control algorithm if a packet is dropped. We show that N-TCP also works for Mobile ad hoc networks.

We present a transaction commit protocol, "Transaction Commit On Timeout (TCOT)," based on a "timeout" approach for Mobile Database Systems (MDS), which can be universally used to reach a final transaction termination decision (e.g., commit, abort, etc.) in any message-oriented system. Particularly suited for a wireless environment, a timeout mechanism is the only way to minimize the impact of the slow and unreliable wireless link. We compare TCOT to a modified version of 2PC to show its superiority based on commit time.

After a "boom" period from the late 80s to the early 90s, there appears to have been a reduction in the amount of work published on Concurrency Control (CC) in real-time database systems (RTDBS) in general and firm RTDBS in particular. This may be because existing paradigms (e.g., Optimistic CC) have been pushed to their limits and it is difficult to extract additional meaningful performance. One of the last unresolved bastions of real-time CC is the successful incorporation of priority cognizance. Researchers have speculated that priority cognizant optimistic concurrency control (OCC) algorithms, if designed well, could outperform priority insensitive ones in real-time database systems. So far, however, there is a distinct lack of conclusive proof available on this topic and the priority cognizant OCC algorithms that have appeared so far in the literature cannot claim unilateral superiority over their priority insensitive relatives. We thus surmise that successful incorporation of priority cognizance may lead to an increase in the performance of OCC protocols in firm RTDBSs. Based on this premise, we analyze the issue of priority cognizance and identify a critical condition that must hold for priority cognizant conflict resolution to work. The condition is that, on the average, the conflict sets of validating transactions should have a "large" number of transactions: We call this a bird in hand more than two in the bush phenomenon. Subsequently, we design a smart priority cognizant OCC variant, which we call OCC-APR, and analyze its performance, as well as that of several other concurrency control algorithms across a wide range of resource contention and system loading parameters. Surprisingly, it turns out that it is very difficult for priority cognizance to work as the above mentioned condition does not, usually,hold. We explain why this occurs and conclude that priority cognizance does not appear to be a promising technique to increase real-time CC performance. The contribution of this paper, thus, is to have laid to rest the "priority cognizance" issue with regard to real-time CCMs.

Materialized views (MV) at the data warehouse (DW) can be kept up to date in response to changes in data sources without accessing data sources for additional information. This process is usually refered to as “self maintenance of views”. A number of algorithms have been proposed for self maintenance of views, which use auxiliary views (AV) to keep some additional information in DW. In this paper we propose an algorithm for self maintainability of multiple MVs using the above approach. Our algorithm generates a simple maintenance query to incrementally maintain an MV along with its AV at DW. The algorithm maintains these views by minimizing the number and the size of the AVs. Our approach provides better insight into view maintenance issues by exploiting the dependencies and constraints that might exist in the data sources and multiple MVs at DW.

Mobile computing has the potential for managing information globally. Data management issues in mobile computing have received some attention in recent times, and the design of adaptive braodcast protocols has been posed as an important probllem. Such protocols are employed by database servers to decide on the content of bbroadcasts dynamically, in response to client mobility and demand patterns. In this paper we design such protocols and also propose efficient retrieval strategies that may be employed by clients to download information from broadcasts. The goal is to design cooperative strategies between server and client to provide access to information in such a way as to minimize energy expenditure by clients. We evaluate the performance of our protocols both analytically and through simulation.

Mobile computing has the potential for managing information globally. Data management issues in mobile computing have received some attention in recent times, and the design of adaptive broadcast protocols has been posed as an important problem. Such protocols are employed by database servers to decide on the content of broadcasts dynamically, in response to client mobility and demand patterns. In this paper we design such protocols and also propose efficient retrieval strategies that may be employed by clients to download information from broadcasts. The goal is to design cooperative strategies between server and client to provide access to information in such a way as to minimize energy expenditure by clients. We evaluate the performance of our protocols analytically.

In mobile computing mobile hosts or mobile units move randomly from one place to another within a well-defined geographical area. This requires some mechanism for identifying the exact location of a mobile host. Such mechanisms are usually referred to as location management and is one of the essential components for supporting mobility. In the past a number of efficient location management schemes have been suggested but they lack adaptability. We believe that an adaptable location management scheme is more desirable because of frequent change in the location of mobile hosts. In this paper, we report a location management algorithm, which adapts to the constant changing scenario. Our algorithm makes use of some of the concepts of location management schemes proposed in the past.

An integrated data structure is presented in this paper which offers multiple access paths for processing different types of queries efficiently. Our approach is to fuse those data structures which offer efficient access path of a particular type. To show the feasibility of our scheme we fused the B/sup +/-tree, the grid file and extendible hashing, using a proper interface. We implemented and measured its performance through simulation modeling. Our results show that the integrated data structure does improve concurrency and offers a higher throughput for a variety of transaction processing workloads. We argue that our scheme is different than creating secondary indexes for improving concurrency.>

The authors present a performance study of two main memory database recovery algorithms, one using a shadow approach and the other update-in-place. The results show that in main memory databases, shadow approach performs better than update-in-place. The authors introduce minor improvements to the shadow scheme and show that the modified algorithm does show further performance improvement.>

The performance of two main-memory database system (MDBS) algorithms is studied. M.H. Eich's (Proc. of the Fifth Int. Workshop on Database Machines., Oct. 1987) and T.J. Lehman's (Ph. D. Thesis, Univ. of Wisconsin-Madison, Aug 1986) algorithms are selected for this study. The investigation indicates that the shadow approach, as used by Eich, has some advantages over the update in-place strategy of Lehman. The shadow approach has faster response for normal transactions even though transaction commit is slower compared to update in-place approach. It is concluded that irrespective of the recovery algorithm an efficient load balancing plays an important part in the performance of the system. It is suggested that processors should be allocated to any kind of activity on a demand basis. It is discovered that individual recovery of lockable units as used in Lehman's algorithm is a better choice since it increases the system availability after a system failure. It also allows background recovery to go in parallel to normal transaction processing.>

A nonsymmetric deadlock-free mutual exclusion algorithm for computer networks is presented. The algorithm requires O(m) messages to synchronize m modes in a lightly loaded system, and the performance approaches a constant k dependent on m as the workload increases. In a medium to heavily loaded system, it outperforms other proposed algorithms and its performance is independent of network topology.>

An estimate of the information a database contains and the quantification of the vulnerability of that database to compromise by inferential methods is discussed. Such a measure could be used to evaluate the deterrent value of extant protection methods and provide a measure of the potential for inferential compromise through the use of one of the known attack tools. The authors explore the use of the concept of entropy as defined for information by C.E. Shannon (1948; 1951), for the purpose of quantifying information content in a database and develop a measure of vulnerability based on entropy. Use of the measure, when exact disclosure through the use of a tracker is anticipated, is characterized for both static and dynamic databases at design and operational time.>