Computer Science

Over the last two decades, we have witnessed a rapid deployment of real-time applications on the Internet and many research works focus on Quality of Service (QoS), in particular using IPv4 (Internet Protocol Version 4). The inevitable exhaustion of the remaining IPv4 address pool has become progressively evident and as a result the evolution of Internet Protocol (IP) continues leading to the deployment of IPv6 QoS. Today, there is limited experience in the deployment of QoS for IPv6 traffic in MPLS backbone networks in conjunction with DiffServ (Differentiated Services) support. DiffServ itself does not have the ability to control the traffic flow whereas MPLS Traffic Engineering (TE) can control the traffic and can set up end-to-end routing path before data can be forwarded. Multi-Protocol Label Switching (MPLS) plays a key role in next generation networks by delivering QoS and traffic engineering features which is helpful in managing traffic when some links or paths are under and...

Over the last two decades, we have witnessed a rapid deployment of real-time applications on the Internet and many research works focus on Quality of Service (QoS), in particular using IPv4 (Internet Protocol Version 4). The inevitable exhaustion of the remaining IPv4 address pool has become progressively evident and as a result the evolution of Internet Protocol (IP) continues leading to the deployment of IPv6 QoS. Today, there is limited experience in the deployment of QoS for IPv6 traffic in MPLS backbone networks in conjunction with DiffServ (Differentiated Services) support. DiffServ itself does not have the ability to control the traffic flow whereas MPLS Traffic Engineering (TE) can control the traffic and can set up end-to-end routing path before data can be forwarded. Multi-Protocol Label Switching (MPLS) plays a key role in next generation networks by delivering QoS and traffic engineering features which is helpful in managing traffic when some links or paths are under and/or over utilized This paper presents a QoS performance study of some applications such as voice, video conferencing, mail and web over DiffServ with MPLS in IPv4/IPv6 networks using Optimized Network Engineering Tool (OPNET). The effectiveness of DiffServ and MPLS integration in IPv4/IPv6 network is illustrated and analyzed.

Quantum-dot Cellular Automata (QCA) based circuit designs have been explored since its concept development in early 1980’s. Although there are lot of implementation barriers for the development of this nanotechnology to work smoothly at room temperature but the simulated circuit implementations have attracted a large number of researchers towards this new field. The success of metal dot implementation even at very low temperatures has paved a way for exploring new possibilities in computing paradigm. An ample of circuit layouts have been proposed for the design of EX-OR gate, a vital element for arithmetic processes. We have analyzed some reported layouts in terms of their simulation accuracy, latency, cell count and noise performance to propose few single layer robust circuits for their efficient implementation.

Images are being processed and manipulated at every step with the help of modern multimedia tools. In most gaming devices and cartoon series, movement of images are confined or restricted to right, left, up & down directions only. Cellular automata can be successfully applied in image processing. Cellular Automata is a methodology that uses discrete space to represent the state of each element of a domain and this state can be changed according to a transition rule. With our scheme, we are not only able to translate the image into x and y-axis, but also diagonal translations can be achieved. Uniform cellular automata rules are constructed to transform the images in all the directions

In the fast growing information and communication technology (ICT) challenge of data
security is emerging out predominantly due to flow of vital data on the wired and wireless networks.
Cryptosystems have been designed with various techniques of text encryption and decryption. Easy key
encryptions have low level of attack immunity while as complex keys although more resistant to attacks
have other drawbacks of occupying more memory space and low speed of encoding and decoding.
Cryptosystems have been designed with the help of pseudo sequence generation property of cellular
automata too and found relevant due to easy VLSI implementation. We have observed a large number of 2 -
dimensional cellular automata linear rules in odd groups having an ability to generate the original data in
the forward iterations of applied rule. This property is having a versatile fitness for cryptographic
applications. Since almost all additive CA linear rules have been found to have irreversible character both
encryption and decryption of data are possible in forward direction with the difference of iterations only.
The model we can call as Pattern Cryptography, like other CA based models provides easy VLSI
implementation with elegant properties of compact size, high efficiency and high speed at low cost. Since
all odd groups contain such rules to achieve the cryptographic objectives, although with varied
complexity, an additional feature of varied complexity can be incorporated in its VLSI design
implementation.

Cellular Automata rules producing evolution type phenomena have been used for a wide range of applications. Various models have been designed and explored for different applications. Although the strength of its parallelism has been felt by various researchers but its exploration for applications will not minimize the hardware but also maximize the optimum strength of processors. Our present study was intended to identify the additive 2D Cellular Automata linear rules on the quality of pattern evolution and the periodic parallelism utilization. We have made an analysis of 2DCA linear game of life (GOL) rule in Neumann neighborhood pattern evolution and observed pattern multiplication in the process. The results achieved will not only minimize the required hardware for parallel channel creation but also expand the microcomputer processing horizon.

Nanotechnology based QCA basic logic layouts work well while simulating on QCA Designer software. The design of half adders has been reported by various researchers and most of the circuit combinations produce excellent results on simulation. Although design of QCA full adders has been reported by a large number of researchers but the simulation results on most of the circuits fail to produce claimed outputs as such the carry forward work is becoming difficult. There are certain difficulties in producing desired simulation results while joining two half adders to design full adder. The main cause for the problem seems to be the mismatch of input data, when earlier stage data is combined with the forward stage. We have tried to study some full adder designs on the basis of simulation results to move forward with our own designs for the purpose. With analysis of few reported adders we have proposed two full adder circuit layout designs with analysis for efficient implementation and future improvements.

Quantum-dot Cellular Automata (QCA) based circuit designs have been explored since its concept development in early 1980's. Although there are lot of implementation barriers for the development of this nanotechnology to work smoothly at room temperature but the simulated circuit implementations have attracted a large number of researchers towards this new field. The success of metal dot implementation even at very low temperatures has paved a way for exploring new possibilities in computing paradigm. An ample of circuit layouts have been proposed for the design of EX-OR gate, a vital element for arithmetic processes. We have analyzed some reported layouts in terms of their simulation accuracy, latency, cell count and noise performance to propose few single layer robust circuits for their efficient implementation.

In the fast growing information and communication technology (ICT) challenge of data security is emerging out predominantly due to flow of vital data on the wired and wireless networks. Cryptosystems have been designed with various techniques of text encryption and decryption. Easy key encryptions have low level of attack immunity while as complex keys although more resistant to attacks have other drawbacks of occupying more memory space and low speed of encoding and decoding. Cryptosystems have been designed with the help of pseudo sequence generation property of cellular automata too and found relevant due to easy VLSI implementation. We have observed a large number of 2-dimensional cellular automata linear rules in odd groups having an ability to generate the original data in the forward iterations of applied rule. This property is having a versatile fitness for cryptographic applications. Since almost all additive CA linear rules have been found to have irreversible character both encryption and decryption of data are possible in forward direction with the difference of iterations only. The model we can call as Pattern Cryptography, like other CA based models provides easy VLSI implementation with elegant properties of compact size, high efficiency and high speed at low cost. Since all odd groups contain such rules to achieve the cryptographic objectives, although with varied complexity, an additional feature of varied complexity can be incorporated in its VLSI design implementation.

Quantum-dot cellular automata (QCA) is among the most promising nanotechnologies as the substitution for the current metal oxide semiconductor field effect transistor based devices. Therefore, lots of attention have been paid to different aspects to improve the efficiency of QCA circuits. In this way, the adder circuits are widely investigated since their performance can directly affect the whole digital system performance. In this paper, a new ultra-high speed QCA full adder cell is proposed based on multi-layer structures. The proposed full adder cell is simple in design using 3-input Exclusive-OR (TIEO), which computes the Sum bits and Majority gate, which computes the Carry bits. To verify the efficacy of the presented full adder cell, it is considered, the main constructing block in 4-bit ripple carry adder circuit. Hence, significant improvements in terms of area and cell count have been achieved. Particularly simulation results show 20% and 1.8% reduction respectively in the area and cell count overhead. Detailed performance evaluation and structural analysis are performed in different aspects to authenticate the proposed circuits (one-bit and 4-bit) having superb performance in comparison to previously reported works. QCADesigner CAD tool has been used to verify the correct functionality of the proposed architectures.

Cellular Automata rules producing evolution type phenomena have been used for a wide range of applications. Various models have been designed and explored for different applications. Although the strength of its parallelism has been felt by various researchers but its exploration for applications will not minimize the hardware but also maximize the optimum strength of processors. Our present study was intended to identify the additive 2D Cellular Automata linear rules on the quality of pattern evolution and the periodic parallelism utilization. We have made an analysis of 2DCA linear game of life (GOL) rule in Neumann neighborhood pattern evolution and observed pattern multiplication in the process. The results achieved will not only minimize the required hardware for parallel channel creation but also expand the microcomputer processing horizon.

Images are being processed and manipulated at every step with the help of modern multimedia tools. In most gaming devices and cartoon series, movement of images are confined or restricted to right, left, up & down directions only. Cellular automata can be ...

This paper helps investigate the integration of information technology (IT) and simulation in order to help understand how to set reliable delivery dates in manufacturing-logistics networks.  This integration is necessary to assist organizations involved in the network to help plan and control their operations more efficiently.  The authors reviewed previous work in the areas of IT-oriented logistics, real time simulation, and due date assignment.  We describe a general architecture for a real-time simulation-based system and create a prototype based on our architecture.  An application of the prototype in a small manufacturing company is employed.  The prototype implemented was for a local manufacturer of made-to-order safety windows with three manufacturing plants and a one office location, all within a 50-mile radius.  The prototype for this company was developed utilizing a Boreland’s Delphi 3 application development tool.  The reason that a distributed simulation model was not ...

Integrating cooperative learning techniques with information technology and applying it to the field of Production and Operations Management (P/OM) will help to investigate how Computer-Supported Cooperative Learning (CSCL) can enhance learning performance of students. Research in CSCL provides evidence that collaborative communication technology can be a better mechanism to add value to education. Most studies, however, have examined learning performance only during the middle and end of the learning process. Thus, it is not clear how information technology can continuously facilitate and improve student performance and learning experience over time. The purpose of this research is to examine how information technology, when applied to communication medium, can facilitate the learning process in the field of production and operations management. This study compared traditional, face-to-face cooperative learning environments to computer-supported cooperative learning environments fo...

In this paper, we consider several mathematical and algorithmic problems which arise naturally in the optimal deployment of modern network management systems. Specifically, we will consider the problem of minimizing the total communication costs within an architecture consisting of a distributed hierarchy of cooperating intelligent agents. We consider several communication cost models, and describe provable optimal schemes for distributing agents among machines in each of these models.

There is considerable research relating the structure of Boolean networks to their state space dynamics. In this paper, we extend the standard model to include the effects of thermal noise, which has the potential to deflect the trajectory of a dynamical system within its state space, sending it from one stable attractor to another. We introduce a new "thermal robustness" measure, which quantifies a Boolean network's resilience to such deflections. In particular, we investigate the impact of structural homogeneity on two dynamical properties: thermal robustness and attractor density. Through computational experiments on cyclic Boolean networks, we ascertain that as a homogeneous Boolean network grows in size, it tends to underperform most of its heterogeneous counterparts with respect to at least one of these two dynamical properties. These results strongly suggest that during an organism's growth and morphogenesis, cellular differentiation is required if the organism seeks to exhibit both an increasing number of attractors and resilience to thermal noise.

Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common over-arching mission objectives which predicate a cooperativeness on the part of constituent nodes. In this article we present a new strategy to improve MANET communications based on node cooperation with respect to mobility. We present our model for cooperative mobility, and use this cost-benefit framework to explore the impact of cooperation in MANETs where nodes are-to varying extents-willing to be moved for the common good. We develop an effective centralized algorithm for mobility planning based on multigrid techniques. Our simulation results are compelling and demonstrate that the communication infrastructure-specifically, connection bit error rate-can be significantly improved by leveraging this proposed scheme.

In this paper, we develop a Cooperative Mobility Model that captures new salient features of collaborative and mission-oriented MANETs. In particular, the cost-benefit framework of our model is a significant advance in modelling heterogenous networks whose nodes exhibit the complete range of autonomy with respect to mobility. We then describe the design of CoopSim, a platform for conducting simulation experiments to evaluate the impact of parameter, policy and algorithm choices on any system based on the proposed Cooperative Mobility Model. We present a small but illustrative case study and use the experimental evidence derived from it to give an initial evaluation of the merits of the proposed model and the efficacy of the CoopSim software. In our case study, we propose studying the impact of the proposed model on improving the end-to-end communication based on the QoS parameter, namely BER.

Hospital facilities use a collection of heterogeneous devices, produced by many different vendors, to monitor the state of patient vital signs. The limited interoperability of current devices makes it difficult to synthesize multivariate monitoring data into a unified array of real-time information regarding the patients state. Without an infrastructure for the integrated evaluation, display, and storage of vital sign data, one cannot adequately ensure that the assignment of caregivers to patients reflects the relative urgency of patient needs. This is an especially serious issue in critical care units (CCUs). We present a formal mathematical model of an operational critical care unit, together with metrics for evaluating the systematic impact of caregiver scheduling decisions on patient care. The model is rich enough to capture the essential features of device and patient diversity, and so enables us to test the hypothesis that integration of vital sign data could realistically yield a significant positive impact on the efficacy of critical care delivery outcome. To test the hypothesis, we employ the model within a computer simulation. The simulation enables us to compare the current scheduling processes in widespread use within CCUs, against a new scheduling algorithm that makes use of an integrated array of patient information collected by an (anticipated) vital sign data integration infrastructure. The simulation study provides clear evidence that such an infrastructure reduces risk to patients and lowers operational costs, and in so doing reveals the inherent costs of medical device non-interoperability.

This paper presents a new method for obtaining network properties from incomplete data sets. Problems associated with missing data represent well-known stumbling blocks in Social Network Analysis. The method of "estimating connectivity from spanning tree completions" (ECSTC) is specifically designed to address situations where only spanning tree(s) of a network are known, such as those obtained through respondent driven sampling (RDS). Using repeated random completions derived from degree information, this method forgoes the usual step of trying to obtain final edge or vertex rosters, and instead aims to estimate network-centric properties of vertices probabilistically from the spanning trees themselves. In this paper, we discuss the problem of missing data and describe the protocols of our completion method, and finally the results of an experiment where ECSTC was used to estimate graph dependent vertex properties from spanning trees sampled from a graph whose characteristics were known ahead of time. The results show that ECSTC methods hold more promise for obtaining network-centric properties of individuals from a limited set of data than researchers may have previously assumed. Such an approach represents a break with past strategies of working with missing data which have mainly sought means to complete the graph, rather than ECSTC's approach, which is to estimate network properties themselves without deciding on the final edge set.