انجمن کامپیوتر ایران

Recent studies have shown in which extent peerto- peer file sharing traffic occurs in the global Internet. Mobile users want the same type of service, thus supporting them with peer-to-peer applications is naturally the next step. The main goal in the design of proposed architecture was to provide searching for shared files not only among vehicles during opportunistic meetings, but also among all vehicles in the Vehiclular Ad Hoc Networks. In this architecture new roles to access points are attributed. A key point in this plan is to build clusters and choose supernodes. An important criterion for any choice making no doubt is the minimization of message overhead. In this Paper the influence of incorporating vehicles traffic in the organization of access points, add to connection of distant vehicles has been studied. I have built a stable architecture providing support for a high dynamic environment beside conceiving a protocol supporting for this architecture. In addition to traditional services of indexing and searching, strategies for a cost effective car-positions management, synchronization of requests and deliveries have been developed.

Multiprocessor scheduling belongs to a special category of NP-complete computational problems. The purpose of scheduling is to scatter tasks among the processors in such a way that the precedence constraints between tasks are kept, and the total execution time is minimized. Cellular automata (CA) can be used for multiprocessor scheduling, but one of the difficulties in using CA is the exponentially increasing number of rules with increasing number of processor and neighborhood radius. Here, we propose a combined use of ant colony and evolutionary meta-heuristics to search the rule’s feasible space in order to find optimal rule base. Also we introduce a two dimensional cellular automata structure based on the important task attributes in the precedence task graph. The proposed scheduler that uses evolving cellular automata based on ant colony can find optimal response time for some of well known precedence task graph in the multiprocessor scheduling area.

Two new high-performance Full Adders, purely designed with 3-input Majority-not function, are proposed in this paper. The Majority-not function is implemented efficiently by using only capacitors and a static CMOS inverter. This kind of design improves the parameters of the Full Adder cell and leads to high performance, driving capability, a high degree of regularity and simplicity. Five state-of-the-art 1-bit Full Adder cells and the proposed Full Adders are simulated using 0.18μm CMOS technology at three supply voltages. Simulation results demonstrate significant improvement in terms of power consumption and Power-Delay Product (PDP).

We address, in this paper, the problem of estimating the input sequence of a known, non-minimum phase, FIR system, when a large number of its roots are located near or on the unit circle. This issue cannot be solved by conventional methods known to date. Recently, algorithms based on spectral factorization are considered as possible solutions of inversing nonminimum phase systems but, these techniques cannot prohibit the instability of the systems whose roots are located on the unit circle. We propose an alternative method based on adaptive filtering resulted from a new point of view of the deconvolution problem that avoids inversing the system. The LMS adaptive filter is used to meet our objective while faster implementation than optimization-based techniques, be it gradient based or genetic, is achieved. Moreover, the technique is validated by experimental results, in simulated cases, which are mainly focused on large sequence of signals in noisy conditions.

In this paper, a fuzzy inference system by which reliability of features can be measured is designed. The reliability determines discriminative power of a feature in separating target from background. We focus our attention on design of membership functions. With a rational explanation on available information over a particle filter-base tracking process, we infer a coarse estimation of membership functions. It follows with a fine-tuning stage by using genetic algorithm. Color, edge, texture and TED are used in current work but the extension to a wider number of features is straightforward.

Particle Swarm Optimization (PSO) is an optimization method that is inspired by nature and is used frequently nowadays. In this paper we proposed a new dynamic geometric neighborhood based on Voronoi diagram in PSO. Voronoi diagram is a geometric naturalistic method to determine neighbors in a set of particles. It seems that in realistic swarm, particles take Voronoi neighbors into account. Also a comparison is made between the performance of some traditional methods for choosing neighbors and new dynamic geometric methods like Voronoi and dynamic Euclidean. In this comparison it is found that PSO with geometric neighborhood can achieve better accuracy overall especially when the optimum value is out of the initial range.

PEnT1 is an automatic English to Persian text translator. It translates simple English sentences into Persian, exploiting a combination of rule based and semantic approaches. It covers all the twelve tenses in English in both passive and active verbs for indicative, negative, interrogative sentences. In this paper, introducing PEnT1, we propose a new WSD method by presenting a hybrid measure to score different senses of a word. We also discuss prototyping some linguistic resources to test our methods.

The dynamic nature of service-oriented architecture (SOA), leads to a need for special attention about the turbulence of the quality attributes (or non-functional requirements) of software during the dynamic changes. If there exists a method for monitoring the whole quality of a service-oriented software, the service selector component of the architecture, which has the responsibility of choosing the best candidate service at runtime, can be aware of the quality state of the whole software at any moment of decision. In this paper, we have focused on the overall quality of an architecture which consists of multiple independent services and present a new method for tracing quality attributes in service oriented architecture based on Graph Transformation System (GTS) as a formal approach.