149 research outputs found

    Assessment of query reweighing, by rocchio method in farsi information retrieval

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    Due to the lack of users knowledge of the collections used by search engines and in general retrieval systems, users can not express their information need appropriately in queries. In other words, they do not have enough experience to formulate their needs to find related documents. The idea of user’s query expansion aims to help users to improve and correct the queries. In fact, retrieval system, regarding the feedback it receives from user at the first stage, moves the query in set space to more related documents. Different approaches in information retrieval systems have been used; however, there has not been any assessment of efficacy of query expansion in Farsi information retrieval systems. In this paper, expansion basic model of Rocchio, assessed as the primary model to retrieve Farsi documents, has been presented. As a matter of fact, the purpose of this study is to determine the effect of a standard and basic model on query expansion to retrieve Farsi documents, so that the researchers can compare their achievements of query expansion with the findings of this paper which showed a straightforward and positive effect on Farsi document retrieval

    Checking and Enforcing Security through Opacity in Healthcare Applications

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    The Internet of Things (IoT) is a paradigm that can tremendously revolutionize health care thus benefiting both hospitals, doctors and patients. In this context, protecting the IoT in health care against interference, including service attacks and malwares, is challenging. Opacity is a confidentiality property capturing a system's ability to keep a subset of its behavior hidden from passive observers. In this work, we seek to introduce an IoT-based heart attack detection system, that could be life-saving for patients without risking their need for privacy through the verification and enforcement of opacity. Our main contributions are the use of a tool to verify opacity in three of its forms, so as to detect privacy leaks in our system. Furthermore, we develop an efficient, Symbolic Observation Graph (SOG)-based algorithm for enforcing opacity

    Information-rich quality controls prediction model based on non-destructive analysis for porosity determination of AISI H13 produced by electron beam melting

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    The number of materials processed via additive manufacturing (AM) technologies has rapidly increased over the past decade. As of these emerging technologies, electron beam powder bed fusion (EB-PBF) process is becoming an enabling technology to manufacture complex-shaped components made of thermal-cracking sensitive materials, such as AISI H13 hot-work tool steel. In this process, a proper combination of process parameters should be employed to produce dense parts. Therefore, one of the first steps in the EB-PBF part production is to perform the process parameter optimization procedure. However, the conventional procedure that includes the image analysis of the cross-section of several as-built samples is time-consuming and costly. Hence, a new model is introduced in this work to find the best combination of EB-PBF process parameters concisely and cost-effectively. A correlation between the surface topography, the internal porosity, and the process parameters is established. The correlation between the internal porosity and the melting process parameters has been described by a high robust model (R-adj(2) = 0.91) as well as the correlation of topography parameters and melting process parameters (R-adj(2) = 0.77-0.96). Finally, a robust and information-rich prediction model for evaluating the internal porosity is proposed (R-adj(2) = 0.95) based on in situ surface topography characterization and process parameters. The information-rich prediction model allows obtaining more robust and representative model, yielding an improvement of about 4% with respect to the process parameter-based model. The model is experimentally validated showing adequate performances, with a RMSE of 2% on the predicted porosity. This result can support process and quality control designers in optimizing resource usage towards zero-defect manufacturing by reducing scraps and waste from destructive quality controls and reworks

    A faunistic study and population fluctuations of mites associated with stored wheat in Tehran region, Iran

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    In order to carry out a faunistic study on mites and their abundance in stored wheat in Tehran, Karaj and Varamin, mite samples were collected from stored wheat, straw and dust in silos, flour-mills and mills during spring 2005. Twenty-five species belonging to 11 families and three orders including Astigmata, Prostigmata and Mesostigmata were identified, of which five species, viz. Aleuroglyphus ovatus (Troupeau), Tyrolichus casei (Oudemans), Acarophenax tribolii (Newstead & Duvall), Cheyletus eruditus (Schrank) and Erythraeus garmsaricus Saboori et al., are newly recorded from wheat stores of Tehran province. The most abundant predator and pest mites were Acaropsellina sollers (Kuzin) (Cheyletidae) and Acarus siro (L.) (Acaridae), respectively. The highest observed number of mites was, in sequence: Tehran Silo, Ard-Iran flour-mill and Jafar Joshaghani mill

    Ti-6Al-4V lattice structures produced by EBM: Heat treatment and mechanical properties

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    Additive manufacturing (AM) processes allow producing the complex components in a layerwise fashion. The complexity includes the design of lighter and stronger components by using lattice structures that can be quickly realized through AM technologies. However, the mechanical behaviour of lattice structures is not completely known, especially in the post-treated state. Thus, this work aims to explore the effect of post-treatment on the compressive strength of specimens with lattice structures. The samples are produced using Ti-6Al-4V powder processed by Electron Beam Melting (EBM). The outcomes of this work confirm the correlation between the heat treatment and final mechanical properties

    Fault-tolerant Cooperative Tasking for Multi-agent Systems

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    A natural way for cooperative tasking in multi-agent systems is through a top-down design by decomposing a global task into sub-tasks for each individual agent such that the accomplishments of these sub-tasks will guarantee the achievement of the global task. In our previous works [1], [2] we presented necessary and sufficient conditions on the decomposability of a global task automaton between cooperative agents. As a follow-up work, this paper deals with the robustness issues of the proposed top-down design approach with respect to event failures in the multi-agent systems. The main concern under event failure is whether a previously decomposable task can still be achieved collectively by the agents, and if not, we would like to investigate that under what conditions the global task could be robustly accomplished. This is actually the fault-tolerance issue of the top-down design, and the results provide designers with hints on which events are fragile with respect to failures, and whether redundancies are needed. The main objective of this paper is to identify necessary and sufficient conditions on failed events under which a decomposable global task can still be achieved successfully. For such a purpose, a notion called passivity is introduced to characterize the type of event failures. The passivity is found to reflect the redundancy of communication links over shared events, based on which necessary and sufficient conditions for the reliability of cooperative tasking under event failures are derived, followed by illustrative examples and remarks for the derived conditions.Comment: Preprint, Submitted for publicatio

    Aquaporins: relevance to cerebrospinal fluid physiology and therapeutic potential in hydrocephalus

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    The discovery of a family of membrane water channel proteins called aquaporins, and the finding that aquaporin 1 was located in the choroid plexus, has prompted interest in the role of aquaporins in cerebrospinal fluid (CSF) production and consequently hydrocephalus. While the role of aquaporin 1 in choroidal CSF production has been demonstrated, the relevance of aquaporin 1 to the pathophysiology of hydrocephalus remains debated. This has been further hampered by the lack of a non-toxic specific pharmacological blocking agent for aquaporin 1. In recent times aquaporin 4, the most abundant aquaporin within the brain itself, which has also been shown to have a role in brain water physiology and relevance to brain oedema in trauma and tumours, has become an alternative focus of attention for hydrocephalus research. This review summarises current knowledge and concepts in relation to aquaporins, specifically aquaporin 1 and 4, and hydrocephalus. It also examines the relevance of aquaporins as potential therapeutic targets in hydrocephalus and other CSF circulation disorders

    Assessment of Query Reweighing, by Rocchio Method in Farsi Information Retrieval

    Get PDF
    Due to the lack of users knowledge of the collections used by search engines and in general retrieval systems, users can not express their information need appropriately in queries. In other words, they do not have enough experience to formulate their needs to find related documents. The idea of user’s query expansion aims to help users to improve and correct the queries. In fact, retrieval system, regarding the feedback it receives from user at the first stage, moves the query in set space to more related documents. Different approaches in information retrieval systems have been used; however, there has not been any assessment of efficacy of query expansion in Farsi information retrieval systems. In this paper, expansion of basic model of Rocchio, assessed as the primary model to retrieve Farsi documents, has been presented. As a matter of fact, the purpose of this study is to determine the effect of a standard and basic model on query expansion to retrieve Farsi documents, so that the researchers can compare their achievements of query expansion with the findings of this paper which showed a straightforward and positive effect on Farsi document retrieval
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