Distributed Computing and Internet Technology

The term “Transactional Memory” was coined back in 1993, but even today, there is a vigorous debate about what it means and what it should do. This debate sometimes generates more heat than light: terms are not always well-defined and criteria for making judgments are not always clear.

This article will try to impose some order on the conversation. TM itself can encompass hardware, software, speculative lock elision, and other mechanisms. The benefits sought encompass simpler implementations of highly-concurrent data structures, better software engineering for concurrent platforms and enhanced performance.

Data delivered today over the web reflects rapid and unpredictable changes in the world around us. We are increasingly relying on content that provides dynamic, interactive, personalized experiences. To achieve this, the content of most web pages is created dynamically, by executing queries dynamically, using data that changes dynamically from distributed sources identified dynamically. A typical web page presents a “view” of the world constructed from multiple sources. In this paper, we examine the nature of dynamics of distributed data and discuss fresh approaches to maintain the coherency of the views seen by the users. Achieving such coherency while developing scalable low-overhead solutions poses challenges in terms of delivering data with the required fidelity in spite of data dynamics. How these challenges can be met by the judicious design of algorithms for data dissemination, caching, and cooperation forms the crux of our work.

Malicious Software referred to as Malware refers to a software that has infiltrated to a computer without the authorization of the computer (or the owner of the computer). Typical categories of malicious code include Trojan Horses, viruses, worms etc. Malware has been a major cause of concern for information security. With the growth in complexity of computing systems and the ubiquity of information due to WWW, detection of malware has become horrendously complex. In this paper, we shall survey the theory behind malware to provide the challenges behind detection of malware. It is of interest to note that the power of the malware (or for that matter computer warfare) can be seen in the theories proposed by the iconic scientists Alan Turing and John von Neumann. The malicious nature of malware can be broadly categorized as injury and infection analogously in the epidemiological framework. On the same lines, the remedies can also be thought of through analogies with epidemiological notions like disinfection, quarantine, environment control etc. We shall discuss these aspects and relate the above to notions of computability.

Adleman in his seminal paper has extrapolated protection mechanisms such as quarantine, disinfection and certification. It may be noted that most of the remedies in general are undecidable. We shall discuss remedies that are being used and contemplated. One of the well-known restricted kind of remedies is to search for signatures of possible malwares and detect them before getting it through to the computer. Large part of the current remedies rely on signature based approaches that is, heavy reliance on the detection of syntactic patterns. Recent trends in security incidence reports show a huge increase in obfuscated exploits; note that in the majority of obfuscators, the execution behaviour remains the same while it can escape syntactic recognitions. Further, malware writers are using a combination of features from various types of classic malwares such as viruses and worms. Thus, it has become all the more necessary to take a holistic approach and arrive at detection techniques that are based on characterizations of malware behaviour that includes the environment in which it is expected to execute.

In the paper, we shall first survey various approaches of behavioural characterization of malware, difficulties of virus detection, practical virus detection techniques and protection mechanisms from viruses. Towards the end of the paper, we shall briefly discuss our new approach of detecting malware via a new method of validation in a quarantine environment and show our preliminary results for the detection of malware on systems that are expected to carry a priori known set of software.

In most applications of information technology, the limiting factor is neither computational power nor storage capacity; nor is it connectivity. Hardware can be obtained at commodity prices, and software infrastructure can be downloaded free of charge. The limiting factor is the cost of consistency and coordination: in software development, in systems integration, and in continuing interaction with users. This paper explains how the use of semantic technologies and model-driven engineering can greatly reduce this cost, and thus increase the quality, interoperability, and suitability of information technology applications.

Ad hoc networks are collections of mobile nodes communicating using wireless media without any fixed infrastructure. Existing multicast protocols fall short in a harsh ad hoc mobile environment, since node mobility causes conventional multicast tree to rapidly become outdated. The amount of bandwidth required for building up a multicast tree is less than that required for other delivery structures, since a tree avoids unnecessary duplication of data. In this article, we propose FSIM, a fuzzy controlled source-initiated intelligent multicast routing scheme that takes into account estimated network evolution in terms of residual energy, link stability, position of receivers in the multicast tree etc. Extensive simulation experiments have been conducted to compare performance of FSIM with state-of-the-art tree and mesh-based multicast protocols. The results with respect to a wide range of input parameters show that FSIM attains significantly higher packet delivery ratio at much lesser cost than its competitors.

Coverage is one of the fundamental issues in Wireless Sensor Networks. It reflects how well the service volume is monitored or tracked by its participant sensors. Sensing ranges of nodes are assumed to be of spherical shape, which do not tessellate space. To address this problem, we need to model the sensing range of nodes as space tessellating polyhedra. In this paper, we analyze four such polyhedra, the Cube, Hexagonal Prism, Rhombic Dodecahedron, and Truncated Octahedron based on the number of nodes needed for tessellation, amount of overlapping achieved, and symmetry of lattice. We defined a trade off ratio between the amount of overlapping achieved and the number of nodes deployed. We used this ratio to identify Rhombic Dodecahedron as the polyhedron model for optimal 1-coverage. We also show the scalability of this polyhedron model for K-coverage with deterministic deployment.

In this paper we propose a scheme which provides seamless mobility between GPRS and IEEE 802.11 (WiFi) networks. In the proposed scheme, we envision a single Service Provider, who provides Cellular (GPRS), WLAN (WiFi) as well as data (Internet) services. The Service Provider’s network consists of an ‘Intermediate Switching Network’ (ISN), placed between the data services and the GPRS-WiFi networks. The ISN uses MPLS and MP-BGP to switch data traffic between GPRS and WiFi networks, as per the movements of the user.

The deployment of wireless sensors is very challenging, yet it is one of the most unexplored areas of this domain. In most of the WSN applications, the sensing location is fixed. In this paper, we are describing a deployment tool we have developed for strategic localization and network optimization. Even before going into field deployment, this tool can be used to calculate precisely the location of the nodes and transmission range while considering line of sight and obstacle into account. The JPEG image of the terrain or floor plan and line of sight or obstacle are the input parameters. The algorithm used in this tool addresses two aspects of the problems: how to minimize the range of the sensor nodes while still forming a well connected network and how to find the location of the forwarding nodes such that the energy required in communication is minimum. Based on these algorithms we have developed a tool to calculate the network parameters such as minimum numbers of forwarding nodes, minimum range for each node required to form a well connected mesh network and minimize the power consumption. Our initial experiments with google maps give very encouraging results.

Search Engine ensures efficient Web-page ranking and retrieving. Page ranking is typically used for displaying the Web-pages at client-side. We are going to introduce a data structural model for retrieval of the searched Web-pages. We propose two algorithms in this paper. The first algorithm constructs the Index Based Acyclic Graph generated by multiple ontologies supported crawling and the second algorithm is for calculation of ranking of the selected Web-pages from Index Based Acyclic Graph.

Advanced, service oriented systems can dynamically re-compose service invocations at run time. For this purpose they may opportunistically select services that are available on the Internet or on open platforms in general. In this paper, a multi criteria selection approach is developed on two optimization goals, quality of service and cost of service invocation. Also, stopping theory is applied to optimize the multi criteria service re-composition. An efficient algorithm is presented which is run time capable since it decides within a predefined time frame. The algorithm yields the best possible lower probability bound for taking an optimal choice. The applied theory is confirmed in simulation experiments.

Currently there is rising interest in using REST architecture to implement business processes. To avoid duplicate designs of similar processes, abstract business processes are used to support for reusability. The modeling of abstract business processes based on RESTful architecture, however has been ignored. This paper abstract the similarities between isomorphic processes by introduce a template process in RESTful architecture. BPEL is extended by introducing the concept of resource. A case study is given to illustrate the effectiveness of the approach. This reusable mechanism has the potential to remedy the problems of duplicate designs in RESTful architecture, and can also help inter-organizational applications obtain high maintainability.

Many existing grid authorization systems adopt an inefficient structure of storing security policies for the available resources, which reduces the scalability and leads to huge repetitions in checking security rules. One of the efficient mechanisms that handles these repetitions and increases the scalability is the Hierarchical Clustering Mechanism (HCM) [1]. HCM outperforms the Brute Force Approach as well as the Primitive Clustering Mechanism (PCM). This paper enhances HCM to accommodate the dynamism of the grid and the same is demonstrated using new algorithms.

Negotiation in business is natural and so it is while business is performed on world wide web. There has been investigation on to perform negotiation on web. In this paper, we view negotiation is a process and propose a framework for it’s implementation.

Batch service queues have been discussed extensively over the last several years and applied in the areas of transportation systems, telecommunication systems and computer operating systems, see Neuts [1], Chaudhry and Templeton [2], Medhi [3], etc. In accessible batch service queues, the arriving customers will be considered for service with current batch service in progress with some limitation. The concept of accessibility into batches during service has been considered by Gross and Harris [4], Kleinrock and [5]. The infinite buffer queue with accessible and non-accessible batch service rule has been studied by Sivasamy [6], wherein the arrivals and services are exponentially distributed. A similar model with finite and infinite buffer in discrete-time case has been studied by Goswami et al. [7].

The problem of coordinating a set of autonomous, mobile robots for cooperatively performing a task has been studied extensively over the past decade. These studies assume a set of autonomous, anonymous, oblivious robots. A task for such robots is to form an arbitrary pattern in the two dimensional plane. This task is fundamental in the sense that if the robots can form any pattern, they can agree on their respective roles in a subsequent, coordinated action. Such tasks that a system of robots can perform depend strongly on their common agreement about their environment. In this paper, we attempt to provide a distributed algorithm for pattern formation in the case of no agreement on coordinate axes. We also discuss the limitations of our algorithm.

Gathering of multiple robots is a well known and challenging research problem. Most of the existing works consider the robot to be dimensionless (point). Algorithm for Gathering fat robots (unit disc robots) has been reported for 3 and 4 robots. This paper proposes a distributed algorithm for Gathering n (n ≥ 5) autonomous, oblivious, homogeneous, asynchronous, fat robots. The robots are assumed to be transparent and they have full visibility.

With ever growing interests in High Performance Computer (HPC) systems for their inherent capabilities for data consolidation, data modeling, systems simulation, data storage, or intensive computation solutions there will obviously be ever growing needs from researchers within governments, businesses, and academia to determine the right HPC framework for meeting their computational needs for the least cost. While HPC simulators are available from commercial sources, they are not free and often commit a group into design choices that are not always optimal. In this short paper, we present our preliminary effort to design an open-source, adaptable, free-standing and extendible HPC simulator.

This paper analyzes Finite buffer Discrete-time single and batch service queueing system. The inter-arrival times of successive arrivals are assumed to be independent and geometrically distributed. The customers are served by a single-server either one at a time or in batches depending upon the number of customers present in the system. The service times are assumed to be independent and geometrically distributed. The analysis of this queueing model is based on the use of the recursive method. The steady-state probabilities for the late arrival systems with delayed access and some performance measures such as the average number of customers in the queue and expected busy period with computational experiences have been presented.

The efficiency of a Peer-to-Peer file sharing overlay is dependent on the lookup procedure. Huge size of peer-to-peer networks demands a scalable efficient lookup algorithm. In this paper we look at fuzzy logic approach in which we assign probabilities to each node based on the content it has. Lookup is guided by the probabilities. The results show that this algorithm is much better than standard lookup algorithms.

UML being semi formal in nature, it lacks formal syntax and hence automated verification of design specifications cannot be done. To address this we propose a UML Compiler that takes context free grammars for UML diagrams and verifies the syntactic correctness of the individual diagrams and semantic correctness in terms of consistency verification with other diagrams. This UML-Compiler is a part of a framework, which consists of two modules. First module converts XMI format of UML diagrams, as generated by any standard tool into string format and second module (UML-Compiler) is for verification of the diagrams. This paper focuses on the second module and proposes a formal context free grammar for the two of the commonly used UML diagrams - Class diagram (depicting the static design) and sequence diagram (depicting behavioral design) and validated by using Lex and YACC.

Due to short operand size, Hyperelliptic Curve Cryptosystem (HECC) of genus 3 is well suited for all kinds of embedded processor architectures, where resources such as storage, time or power are constrained. In the implementation of HECC, a significant step is the selection of secure hyperelliptic curves on which the Jacobian is constructed and speed up the scalar multiplications in the Jacobians of hyperelliptic curves. In this paper, we have explored various possible attacks to the discrete logarithm in the Jacobian of a Hyperelliptic Curve (HEC) that are to be considered to establish a secure HEC, analysed addition and doubling of divisor which are the prime steps of scalar multiplication and then proposed certain improvements in the existing explicit formula that will result in a performance gain for HECC of genus 3.

Even after thorough testing of a program, usually a few bugs still remain. These residual bugs are randomly distributed through out the code. It is observed that bugs in some parts of a program can cause more frequent and more severe failures compared to those in other parts. So, it is possible to prioritize the program elements at the time of testing according to their potential to cause failures. Based on this idea, we have proposed a metric to compute the influence of an object in an object-oriented program. Influence of an element indicates the potential of the element to cause failures. The intensity with which each element is tested is proportionate to its influence value. We have conducted experiments to compare our scheme with related schemes. The results establish that the failure rate can indeed be minimized using our scheme when the software is executed for some duration after the completion of testing phase. Our proposed metric can be useful in applications such as coding, debugging, test case design and maintenance etc.

In 2000, Sun proposed an efficient smart card based remote user authentication scheme to improve the efficiency of Hwang and Li’s scheme. In 2002, Chien et al. demonstrated that Sun’s scheme only achieves unilateral user authentication so that only authentication server authenticates the legitimacy of the remote user and proposed a new remote user authentication scheme. In 2004, Hsu demonstrated that Chien et al.’s scheme is vulnerable to parallel session attack. In 2005, Lee et al. proposed an improved scheme to overcome this weakness while maintaining the merits of Chien et al.’s scheme. In 2005, Yoon and Yoo found that Lee et al.’s scheme is vulnerable to masquerading server attack and proposed an improved scheme. In 2009, Xu et al. demonstrated that Lee et al.’s scheme is vulnerable to offline password guessing attack and proposed an improved scheme. However, we found that Lee et al.’s scheme is also vulnerable to impersonation attack, malicious user attack and reflection attack. Moreover, Lee et al.’s scheme fails to protect the user’s anonymity in insecure communication channel. This paper presents an improved scheme to resolves the aforementioned problems, while keeping the merits of Lee et al.’s scheme.

Although regular graphs have a long history, some of their properties such as diameter, symmetry, extensibility and resilience do not seem to have received enough attention in the context of network design. The purpose of this paper is to present some interesting theoretical results concerning regular graphs pertinent to optimal network design.

Specification based testing involves generating test cases from the specification, here, UML. The number of automatically generated test scenarios from UML activity diagrams is large and hence impossible to test completely. This paper presents a method for selection of test scenarios generated from activity diagrams using Levenshtein distance. An activity diagram is transformed into a directed graph representing the sequence of activities. A modified Depth First Algorithm(DFS) is applied to obtain test scenarios. Levenshtein distance is calculated between the scenarios thus generated. The objective is to select the less similar test cases and at the same time provide maximum coverage.

Models for the processes by which ideas and influences propagate through a social network have been studied in number of domains, including the diffusion of medical and technological innovations, the sudden and widespread adoption of various strategies in game-theoretic settings, and the effects of ’word of mouth’ in the promotion of new products. The problem of selecting a set of most influential nodes in a network has been proved to be NP-hard. We propose a framework to analyze the network in depth and to find the set of most influential nodes. We consider the problem of selecting, for any given positive integer k, the most influential k nodes in a Academic Social Network (ASN), based on certain criterions relevant in academic environment like number of citations, working location of authors, cross reference and cross co-authorship. Based on the initial node set selection and the diffusion model, we study the spread of influence of the influential nodes in the academic network. Appropriate criterions are used in the proposed generalized diffusion models. In this paper, we used two different models; (1) Linear Threshold Model and (2) Independent Cascade model to find the set of influential nodes for different criterions in an ASN and compared their performances. We constructed ASN based on the information collected from DBLP, Citeseer and used Java Social Network Simulator (JSNS) for experimental simulations.

Maternal mortality is death of any woman while pregnant or 42 completed days during post partum period. Maternal Mortality Rates (MMRs) measures the risk of dying from pregnancy. This is expressed as number of deaths per 100000 births. According to Patel et al[1] 70.69 % of maternal deaths within 24 hours of admission in the hospital are due to geographic conditions, lack of qualified medical attention, delayed referral and late intervention. Therefore a vast majority of these deaths are preventable [2]. Our current study involves developing a “risk assessment method” [Fig. 1] based on a simple health scoring scheme [3], [4]. Using this method we can provide first advisory and referral services to patients in rural and far flung areas through health workers working in sub centres, PHCs and CHCs [Fig. 2]. These services are delivered through SMS [5] or WAP [6]. Similar scoring schemes have already been tested for its efficacy in Indian conditions on 490 mothers [4]. The previous scoring schemes lacked the transport variable which is important as around 56.67% patients die within 6 hours of admission in the hospital, thereby highlighting the necessity of quick transport [7]. Thus we refined the existing model by adding a transport variable. When we introduced this system in Phringia Block of Kandhamal District, Orissa, India in the form of printed manuals, we saw 100% decline in MMR [Table 1] over a period of two years. The scoring scheme being one of the factors behind it but the specific impact of it was not quantitatively measured. Total risk scores (calculated from Table 2) and associated risk category are 0-2 (Low), 3-5 (Moderate), >6(High). Based on risk category relevant advisory are provided [8].