Sharif Digital Repository

The importance of good weighting methodology in information retrieval methods - the method that affects the most useful features of a document or query representative - is examined.. Weighting features is the thing that many information retrieval systems are regarding as being of minor importance as compared to find the feature and the experiments are confirming this. There are different methods for the term weighting such as TF*IDF and Information Gain Ratio which have been used in information retrieval systems, the paper provides a brief review of the related literature. This paper explores using GA for concept weighting which is a novel application to the field of text mining It proposes... 

In this study, an inventory system consisting of a single product, one supplier, and multiple identical retailers is considered. Each retailer replenishes inventory from the supplier according to the well known (R,Q) policy. Transit times are constant and retailers face independent Poisson demand. The supplier utilizing the retailers' information in decision making for replenishment policy with a given order size starts with m initial batches (of size Q) and places an order in a batch of size Q to an outside source when a new order is placed. In this inventory system, excess demand is backordered, delayed orders are satisfied on a first-come first-serve basis, and no partial shipment is... 

From searching music with smartphones to broadcast monitoring by radio channels, audio identification systems are being used more in recent years. Design of such systems may differ when the problem domain changes, since each environment has special conflicting constraints to consider, like required speed and robustness to signal degradations. In this paper, a widely used audio identification system originally developed by Haitsma and Kalker is analyzed from a signal processing point of view and the fingerprint (audio feature) extraction method is modified. By adding a flexible filter to the fingerprint extraction method, the original system can be tuned to work in different domains. In order... 

Recognizing TimeML events and identifying their attributes, are important tasks in natural language processing (NLP). Several NLP applications like question answering, information retrieval, summarization, and temporal information extraction need to have some knowledge about events of the input documents. Existing methods developed for this task are restricted to limited number of languages, and for many other languages including Persian, there has not been any effort yet. In this paper, we introduce two different approaches for automatic event recognition and classification in Persian. For this purpose, a corpus of events has been built based on a specific version of ISO-TimeML for Persian.... 

In this investigation, the idea of Visual Working Memory (VWM) mechanism modeling based on versatile fuzzy method; Active Learning method, is presented. Visual information process; retrieving and learning rely on the use of Ink Drop Spread (IDS) and Center of Gravity (COG) as spatial density convergence operators. IDS modeling is characterized by processing that uses intuitive pattern information instead of complex formulas, and it is capable of stable and fast convergence. Furthermore, because it approves that distortion in retrieving irrelative data is adaptive to avoid storing lots of repetitive external information in daily visualization. Subsequently, this distortion is analyzed via two... 

In this paper, we study the problem of private function computation, where a user wants to compute a function of some inputs, using N in mathbb{N} servers, where the function is a private combination/composition of some K in mathbb{N} public basic functions {f 1 , f 2 ,., f K }. More precisely, for some inputs W m , m [1 : M], the user's goal is to calculate hleft( {{W-m}} ight) = sumolimits-{j = 1}^J {{alpha -j}} {h-j}left( {{W-m}} ight), for some J in mathbb{N}, some scalers α j , j [1 : J], and some functions h j (.), j [1 : J], where each is an arbitrary compositions of the basic functions {f 1 , f 2 ,., f K }. The computation is done through a sequence of queries to N servers. In each... 

Rank aggregation, that is merging multiple ranked lists, is a pivotal challenge in many information retrieval (IR) systems, especially in distributed IR and multilingual IR. From the evaluation point of view, being able to calculate the upper-bound of performance of the final aggregated list lays the ground for evaluating different aggregation strategies, independently. In this paper, we propose an algorithm based on dynamic programming which, using relevancy information, obtains the aggregated list with the maximum performance that could be possibly achieved by any aggregation strategy. We also provide a detailed proof for the optimality of the result of the algorithm. Furthermore, we... 

We consider the problem of private information retrieval (PIR), where a single user with private side information (PSI) aims to retrieve multiple files from a library stored at some servers. We assume that the side information (SI) at the user includes a subset of files stored privately. Moreover, the identity of requests and side information at the user are not revealed to any of the servers. The problem involves finding the minimum load transmitted from the servers to the user such that the requested files can be decoded with the help of received data and side information. By providing matching lower and upper bounds for certain regimes, we characterize the minimum load imposed on all the... 

Nowadays, computer is being used in many aspects of human life. A consequence of computer is electronic documents. Computers cannot understand written documents. So, we need to convert written documents to electronic documents in order to be able to process them with computers. One of the common methods for converting written texts to electronic text is Optical Character Recognition (OCR). A lot of work has been done on English OCR, but Persian/Arabic OCR is still under development. One of the major problems in Persian/Arabic OCR is noise removal. Because dots are very important in Persian and Arabic languages and they are very similar to noises, so noise removal from Persian/Arabic... 

Currently there is no standard test collection for evaluation of Farsi information retrieval systems. In this paper we introduce Mahak, the first complete test collection generally available for evaluating Farsi information retrieval systems. In addition, we have used different methods for constructing Mahak qrels and we have compared performance of these methods  

Currently there is no standard test collection for evaluation of Farsi information retrieval systems. In this paper we introduce Mahak, the first complete test collection generally available for evaluating Farsi information retrieval systems. We also discuss our construction process in detail. As a goal, we hope that Mahak will foster the development of Farsi information retrieval systems. © 2007 IEEE  

We consider the problem of private information retrieval (PIR) where a single user with private side information aims to retrieve multiple files from a library stored (uncoded) at a number of servers. We assume the side information at the user includes a subset of files stored privately (i.e., the server does not know the indices of these files). In addition, we require that the identity of requests and side information at the user are not revealed to any of the servers. The problem involves finding the minimum load to be transmitted from the servers to the user such that the requested files can be decoded with the help of received and side information. By providing matching lower and upper... 

Adaptive scheduling schemes which consider channel conditions are examples of cross-layer design in wireless networks. Research work which has been done on optimizing the performance of scheduling systems have shown that in each time slot it is better to transmit to the users with the best channel condition. In order to realize such schemes, most of earlier works have considered perfect feedback channels to send Channel State Information (CSI) to the scheduler. However, in practical systems there are some sources of imperfectness in feedback channels such as delay and quantization error. In this paper, we consider the effect of CSI delay on the performance of such systems. A new delay-aware... 

In an increasing competitive world, marketing survival can be depended simply on timely new information on customers and market trend. One of the most important strategies in CRM (Customer Relationship Management) is to capture enough information from customers and using this information carefully [17, 19]. Of course security of this information is very important in CRM data management [2]. Data management is a method for scheduling and controlling data saving, recovering and processing. This activity has been done continually or periodically [2]. Security level of this information depends on the security policy of the organization. CRM security policy is the directives and practices for... 

In this paper, we propose a new method for automatic news event detection. An event is a specific happening in a particular time and place. We propose a new model in this paper to detect news events using a label based clustering approach. The model takes advantage of the fact that news events are news clusters with high internal similarity whose articles are about an event in a specific time and place. Since news articles about a particular event may appear in several consecutive days, we developed this model to be able to distinguish such events and merge the corresponding news articles. Although event detection is propounded as a stand alone news mining task, it has also applications in... 

We consider a single item, two-level inventory system which consisting of two suppliers and one retailer. Transportation times are constant. The retailer faces Poisson demands and applies continuous (R,Q) policy. Each supplier starts with m initial batches of size Q/2 and places an order in a batch of size Q/2 to an outside source immediately after the retailer's inventory position reaches R+s. In this paper using the idea of the one-for-one ordering policy, we derive the exact value of the expected total cost in the convergent coordinated supply chain. © 2008 IEEE  

E-business requires interoperability of information systems and, therefore, standardization of information sharing. Several XML-based e-business frameworks are developed to define standards for information sharing within and between companies. These frameworks only standardize structure of messages and aren't able to define semantics. The use of Semantic Web Service (SWS) technologies has been suggested to enable more dynamic B2B integration of heterogeneous systems and partners. We present a semantic B2B mediator based on the WSMX -a SWS execution environment, to tackle heterogeneities in RosettaNet messages. We develop a rich RosettaNet ontology and use the axiomatized knowledge and rules... 

Achieving higher transmission rate while reducing transmission power and induced interference on neighboring receivers is deemed necessary for the advancement of future generation networks and is particularly challenging, since these directions could be conflicting in nature. This letter adopts a multiobjective optimization (MOOP) approach to settle the tradeoffs between these three conflicting objectives in orthogonal frequency-division multiple access-based cognitive radio networks. Besides, unlike most of the work in the literature that studied the imperfect channel side information (CSI) of the link between the secondary transmitter and the primary receiver to evaluate ergodic capacity,... 

Deep learning has received much attention as of the most powerful approaches for multimodal representation learning in recent years. An ideal model for multimodal data can reason about missing modalities using the available ones, and usually provides more information when multiple modalities are being considered. All the previous deep models contain separate modality-specific networks and find a shared representation on top of those networks. Therefore, they only consider high level interactions between modalities to find a joint representation for them. In this paper, we propose a multimodal deep learning framework (MDLCW) that exploits the cross weights between representation of... 

In some applicable scenarios, such as community patrolling, mobile nodes are restricted to move only in their own communities. Exploiting the meetings of the nodes within the same community and the nodes within the neighboring communities, a delay tolerant network (DTN) can provide communication between any two nodes. In this paper, two analytical models based on stochastic reward nets (SRNs) are proposed to evaluate the performance of the epidemic content retrieval in such multi-community DTNs. Performance measures computed by the proposed models are the average retrieval delay and the average number of transmissions. The monolithic SRN model proposed in the first step is not scalable, in...