Welcome to Journal of Theoretical and Applied Information Technology

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Among the emerging active sensing radar technology, Multiple Inputs Multiple Output (MIMO) radar has given a new path for imaging and remote sensing techniques. This paper deals with the comparison of performance analysis for various topologies of multiple antenna systems in radars and then compares the obtained result with analogous communication system. This paper also introduces the concept of statistical MIMO radar which exploits the special diversity of target scattering to improve detection and performance due to absence of target fades compared with other types of array radars, analyse various topologies of multiple antenna systems in radars into its analogous multi antenna communication system(AMCM). This new novel detection approach is more tractable than conventional ‘probability of detection analysis’ to track the detection capability of radars and is based on modelling of radar target as a modulator in an analogous communication system. This AMCM method leads to a quantitative and qualitative comparison of the fidelity of MIMO radar and quantifies ‘detection’ as being inversely proportional to bit error rates (BER) of the resulting communications channel. The fundamental difference between statistical MIMO radar and other radar array systems is that the latter seek to maximize the coherent processing gain, while statistical MIMO radar capitalizes on the diversity of target scattering to improve radar performance. Coherent processing is made possible by highly correlated signals at the receiver array, whereas in statistical MIMO radar, the signals received by the array elements are uncorrelated. In this paper the convergence of wireless communication and digital radar is being investigated and their performance is evaluated additionally a system realization between radar & communication technology has been tried for moving vehicle application. The results are found to be encouraging in real life remote sensing system and can be simultaneously used for ITS (intelligent transport system).

MIMO,AMCM,SER and ITS

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In wireless communications, spectrum is a scarce resource and hence imposes a high cost on the high data rate transmission. Fortunately, the emergence of multiple antenna system has opened another very resourceful dimension – space, for information transmission in the air. It has been demonstrated that multiple antenna system provides very promising gain in capacity without increasing the use of spectrum, reliability, throughput, power consumption and less sensitivity to fading, hence leading to a breakthrough in the data rate of wireless communication systems. Since then, multiple-input multiple-output (MIMO) system has become one of the major focuses in the research community of wireless communications and information theory. The study of the performance limits of MIMO system becomes very important since it gives a lot of insights in understanding and designing the practical MIMO systems. There are many schemes that can be applied to MIMO systems such as space time block codes, space time trellis codes, and the Vertical Bell Labs Space-Time Architecture (V-BLAST). In this paper, we study the performance of general MIMO system, the general V-BLAST architecture with Maximum Likelihood (ML), the Successive Interference Cancellation (SIC), Zero-Forcing (ZF), Minimum Mean- Square Error (MMSE) and Maximal Ratio Combining (MRC) detectors in fading channels. Based on bit error rate, we show the performance of these receiver schemes indicates that the ordered SIC detector with Maximum-Likelihood (ML) detection most effectively balances the accuracy of symbol detection. SIC receiver based on ZF or MMSE combined with symbol cancellation and optimal ordering to improve the performance with lower complexity and compare the computational complexity of these schemes with other existence model. Finally, the paper addresses the current questions regarding the integration of MIMO system in practical wireless systems and standards.

MIMO, CCI, ITS, SIC, V-BLAST, ML, STBC, MRC, ZFc

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To increase fault tolerance in distributed database, it is better to add a backup server for each primary server in the system. It is clear that the primary server and backup server need to be connected to each other. To connect these computers to each other when they are in a long distance, it is necessary to use a lease line which needs to be charged as data is transferred. As more packets are transferred between primary and backup server, more money need to be paid for charging this line. So if number of transferred packets between these computers reduces, the company can economize in its expenditures. On the other side, when number of updating information from the primary server to backup server reduces, the number of transaction which should be performed in the backup server reduces.
To achieve this goal, we introduce a new method which reduces the number of transferred packet between primary and backup server. In this method, the replicated data of primary server is used to backup mechanism. In our method the primary server sends transactions in data which are not replicated in other computers. So the transactions on the replicated data are not transferred to backup server, and as a result the numbers of transferred packet get reduce.

Distributed database, Fault tolerance, Remote backup, Data replication, Load balancing, Update filtering.

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Testing is an important phase of quality control in Software development. Software testing is necessary to produce highly reliable systems. The use of a model to describe the behavior of a system is a proven and major advantage to test. In this paper, we focus on model-based testing. The term model-based testing refers to test case derivation from a model representing software behavior. We discuss model-based approach to automatic testing of object oriented software which is carried out at the time of software development. We review the reported research result in this area and also discuss recent trends. Finally, we close with a discussion of where model-based testing fits in the present and future of software engineering

Testing, Object-oriented Software, UML, Model-based testing

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The problem of estimating the Channel State Information (CSI) of several transmitters that communicate with a single receiver is considered. These transmitters communicate with the receiver using orthogonal Space Time Block Codes (OSTBC) method. Based on Rank Revealing LU (RRLU) factorization a novel algorithm to estimate multiuser MIMO channels is proposed. The algorithm estimates the null space of the subspace spanned by the user channels using only a few training blocks to extract the users CSI from this subspace. The proposed algorithm achieves an intermediate performance between Least Squares (LS) based approach and Capon approach. Computer simulations are performed to validate the proposed algorithms

Channel State Information, Channel Estimation, Space Time Block Code, Rank Revealing

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In this paper a real time control for swing-up stabilization of inverted pendulum is designed using Fuzzy logic. In the model proposed here a single rulebase is used to control both position and angle simultaneously during both swing-up and stabilization. The proposed fuzzy control scheme successfully fulfills the control objectives and also has an excellent stabilizing ability to overcome the external impact acting on the pendulum system. The effectiveness of this controller is verified by experiments on a simple inverted pendulum with fixed cart length.

Fuzzy control, Inverted Pendulum, Swing-up Stabilization

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The advantage of the Model Reference Adaptive Scheme is to establish robustness with respect to bounded disturbances and unmodeled dynamics. In the model reference adaptive system (MRAS), the desired index of performance is given by the reference model. The tracking error represents the deviation of the plant output from the desired trajectory. The adaptive control without having robustness property may go unstable in the presence of small disturbances or unmodeled dynamics. A new idea is proposed to reduce the time for adaptation in MRAC systems. The idea behind to design Robust model Reference Adaptive PI control system is by adding the control signal from the PI controller to the control signal from modified MRAC. It has been checked with the lateral dynamic model of Boeing 747 airplane. The proposed controller is easy to implement and has superior transient behavior as compared to the standard adaptive controller and modified adaptive controller.

Model Reference Adaptive Control, Modified Model Reference Adaptive Control, Control Systems, MATLAB.

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The minimum spanning tree clustering algorithm is capable of detecting clusters with irregular boundaries. In this paper we propose minimum spanning trees based clustering algorithm. The algorithm produces k clusters with center and it also creates a dendrogram for the k clusters. The algorithm works in two phases. The first phase of the algorithm produces subtrees. The second phase converts the subtrees into dendrogram. The key feature of the algorithm is it uses both divisive and agglomerative approaches to find Dual similarity clusters.

Euclidean Minimum Spanning Tree, Clustering, Eccentricity, Center, Hierarchical Clustering, Dendrogram , Subtree

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The techniques of secured socket layer (SSL) with client-side certificates for commercial web sites rely on a relatively weak form of password authentication. Browser sends a user’s plaintext password to a remote web server using SSL is vulnerable to attack. In common password attacks, hackers exploit the fact that web users often use the same password at many different sites. This has drawn attention on the need for new hash function designs. In addition the authentication systems which uses passwords stored in a central server is easily prone to attack. To overcome the problem of single server password attacks, the multi-server systems were proposed in which user communicates in parallel with several or all of the servers. Such system requires a large communication bandwidth, complex deployment, needs for synchronization at the user and quite expensive. Optimized two server system is proposed in our work.
The proposal of our work presents a user interface, browser extension password hash, strengthens web password in a two server authentication system. The hash is implemented using a Pseudo Random Function keyed by the password. Since the hash output is tailored to meet server password requirements, the resulting hashed password is handled normally at the server with no server modifications. The two server authentication system is interfaced with client supported hash passwords with server session keys. The two server system contains, the front end service server interacts directly to the user and the back end control server visible to the service server. The users contact only the service server but these two servers are responsible for the authentication of the user. The user has a password which is transformed into two long secrets which are held by service server and control server.

Hash Function, Pseudo random Function,, Password Hash, Two Server Password Authentication , Control Server, Service server