انجمن کامپیوتر ایران

SystemC يک کتابخانهي متن باز از زبان C++ است که امکان طراحي در سطوح بالاي انتزاع را روي اجزاء فراهم مي آورد و براي طراحي سريع و کارا ميتواند مورد استفاده قرار ميگيرد. بهعلاوه، اجازهي توصيف همزمان و يکپارچهسازي اجزاء پيچيده ي سخت افزاري و نرم افزاري را فراهم ميآورد. در اين مقاله، در ابتدا قابليتهاي طراحي وتوصيف مدارا ت آسنکرون به زبان SystemC افزوده شده است. در ادامه پارسري جهت تبديل زبان SystemC به زبان توصيف سخت افزاري آسنکروني Verilog-CSP ارائه مي گردد. با استفاده از اين پارسر، ميتوان مدارهاي آسنکروني را که به وسيله ي SystemC مدلسازي و شبيهسازي ميشود ر ا توسط ابزارهاي سنتز آسنکرون سنتز نمود.

the concept of multi-hop CDMA cellular networks has received increasing attention now. It is a widely accepted assumption that using multi-hopping in cellular networks will increase the cellular throughput. There are several advantages of MCN such as the improved signal quality and higher coverage. Finding an available relaying path is a critical prerequisite for the success of the multi-hop cellular networks and has a great impact on the network throughput. Most works use signal strength, distance and power consumption as routing criteria, but the effect of interference specially intercell interference does not take into account in routing algorithms. For this reason, in this paper interference is calculated at any receiver during the uplink, and a novel routing scheme based on minimum interference and best link gain in each hop, is proposed. Simulation results indicate that the routing algorithm based on our proposed metric results in higher throughput than the other metrics under a certain constraint.

On-chip network interconnections or Network-on- Chip (NOC) is viewed as a possible solution to global wiring issues in highly integrated complex systems. In current NoCs and in order to promote system level integrity, there is a growing need to provide different traffic classes, each with a different Quality-of-Service guarantee. In synchronous NOCs guaranteed service is provided by reserving time slots. Asynchronous NOC implementation, on the other hand, eliminates the need for synchronization when crossing clock domains. In asynchronous NOCs there is no notation of time and arbitration. Any delay in arbitration or refusing requests in arbitration results in the accumulation of data in switch buffers. In this paper a novel arbitration scheme for clockless NOCs has been proposed that is able to service a connection without any halt or jitter in streaming. Consequently, links with a burst traffic pattern and guaranteed bandwidth requirement can be implemented without any large buffers. Simulation results indicate that the proposed method is able to reduce switch buffer size, and hence power consumption in any NoC platform that is providing guaranteed bandwidth requirements in applications with burst data characteristics. For instance, in an MPEG-2 decoder mapped to a 3x2 mesh with 8 guaranteed bandwidth channels in each port, the proposed arbitration scheme is able to reduce the buffer size by 25%. The improvement increases to %47 for a JPEG2000 encoder mapped to a 3x3 mesh.

Web access prediction has attracted significant attention in recent years. Web prefetching and some personalization systems use prediction algorithms. Most current applications that predict the next user web page have an offline component that does the data preparation task and an online section that provides personalized content to the users based on their current navigational activities. In this paper we present an online prediction model that does not have an offline component and fit in the memory with good prediction accuracy. Our algorithm is based on LZ78 and LZW algorithms that are adapted for modeling the user navigation in web. Our model decreases computational complexities which is a serious problem in developing online prediction systems. A performance evaluation is presented using real web logs. This evaluation shows that our model needs much less memory than PPM family of algorithms with good prediction accuracy.

Video processing techniques based on pattern recognition methods and machine vision is one of the interesting research fields which attract many researchers. In this paper, we proposed a novel method for video summarization using genetic algorithm based on information theory. Our method relies on the mutual information for video summarization. The information theory measure provides us with better results because it extracts the inter-frame information. We present that it is a suitable factor for summarizing video, which maintains its integrity.

Keystroke dynamics-based authentication, KDA, verifies users via their typing patterns. To authenticate users based on their typing samples, it is required to find out the resemblance of a typing sample and the training samples of a user regardless of the text typed. In this paper, a measure is proposed to find the distance between a typing sample and a set of samples of a user. For each digraph, histogram-based density estimation is used to find the pdf of its duration time. This measure is combined with another measure which is based on the two samples distances. Experimental results show considerable decrease in FAR while FRR remains constant.

Concept graph is a graph that represents the relationships between language concepts. In this structure the relationship between any two words is demonstrated by a weighted edge such that the value of this weight is interpreted as the degree of the relevance of two words. Having this graph, we can obtain most relevant words to a special term. In this paper, we propose a method for improving the classification of documents from unknown sources by means of concept graph. In our method, initially some features are selected from a training set by a well-known feature selection algorithm. Then, by extracting most relevant words for each class from the concept graph, a more effective feature set is produced. Our experimental results identify an improvement of 1% and 8% in precision and recall measures, respectively.

با افز ايش قيمت ابرکامپ يوترها ا ز طرف ي و ني از به مناب ع محاسباتي با حجم وسيع از طرف ديگر، محقق ين کام پيوتر را بر آن داشته است تا به سراغ استفاده از شبکهاي از منابع محاسبا تي به نا م گريد Grid) روي آورند. گونهاي از گريد به نام گريد محاسباتي Computing Grid مجموعهاي از منابع توزيع شده را براي حل مس ايل با ميزان محاسبات بالا در علوم، مهندس ي و تجارت فراهم آورده اس ت . براي استفاده بهينه از قابليتهاي اين سيستم توزيع شده، الگوريتمه اي زمانبندي کارامدي موردنياز است . در اي ن مقاله الگو ر يتم زمانبن دي جديدي به کمک برنامهسازي ژنتيک و بر مبن اي دو الگور يتم پاي هاي Min-Min و Max-Min طراحي شده است که س ع ي در استفاده از مزاياي اين دو، رفع معايب آنه ا و کوتاه کردن مدت زمانبن د ي نموده است. با مقايسه کارا يي الگو ريتم جدي د با دو الگو ر يتم Min-Min و Max-Min نتايج قابل قبولي بدست آمد.