14,757 research outputs found
Retraction and Generalized Extension of Computing with Words
Fuzzy automata, whose input alphabet is a set of numbers or symbols, are a
formal model of computing with values. Motivated by Zadeh's paradigm of
computing with words rather than numbers, Ying proposed a kind of fuzzy
automata, whose input alphabet consists of all fuzzy subsets of a set of
symbols, as a formal model of computing with all words. In this paper, we
introduce a somewhat general formal model of computing with (some special)
words. The new features of the model are that the input alphabet only comprises
some (not necessarily all) fuzzy subsets of a set of symbols and the fuzzy
transition function can be specified arbitrarily. By employing the methodology
of fuzzy control, we establish a retraction principle from computing with words
to computing with values for handling crisp inputs and a generalized extension
principle from computing with words to computing with all words for handling
fuzzy inputs. These principles show that computing with values and computing
with all words can be respectively implemented by computing with words. Some
algebraic properties of retractions and generalized extensions are addressed as
well.Comment: 13 double column pages; 3 figures; to be published in the IEEE
Transactions on Fuzzy System
Development of the Risk Management Mechanism of an Enterprise Resource Planning System based on Work System Method
This study collects 24 risk-management-relevant research papers published between 2000 and 2010 to elicit significant risk factors and thus develop the risk management mechanism of an enterprise resource planning (ERP) system. The study adopts the grounded theory and conducts an expert questionnaire in order to report its findings on 49 risk factors. Based on the work system method, the identified factors are classified into nine categories and a risk management mechanism is developed thereafter. Finally, to examine the feasibility of the mechanism, two case studies are further investigated. The developed mechanism is found to be a convenient, quick, and proper ERP system risk management tool that can assist enterprises in identifying, analyzing, assessing, and responding to potential risks
Toward Microarcsecond Astrometry for the Innermost Wobbling Jet of the BL Lacertae Object OJ 287
The BL Lacertae object OJ 287 is a very unusual quasar producing a wobbling
radio jet and some double-peaked optical outbursts with a possible period of
about 12 yr for more than one century. This variability is widely explained by
models of binary supermassive black hole (SMBH) or precessing jet/disk from a
single SMBH. To enable an independent and nearly bias-free investigation on
these possible scenarios, we explored the feasibility of extremely
high-precision differential astrometry on its innermost restless jet at
mm-wavelengths. Through re-visiting some existing radio surveys and very long
baseline interferometry (VLBI) data at frequencies from 1.4 to 15.4 GHz and
performing new Very Long Baseline Array (VLBA) observations at 43.2 GHz, we
find that the radio source J08541959, 7.1 arcmin apart from OJ 287 and no
clearly-seen optical and infrared counterparts, could provide a nearly ideal
reference point to track the complicated jet activity of OJ 287. The source
J08541959 has a stable GHz-peaked radio spectrum and shows a jet structure
consisting of two discrete, mas-scale-compact and steep-spectrum components and
showing no proper motion over about 8 yr. The stable VLBI structure can be
interpreted by an episodic, optically thin and one-sided jet. With respect to
its 4.1-mJy peak feature at 43.2 GHz, we have achieved an astrometric precision
at the state-of-art level, about 10 as. These results indicate that future
VLBI astrometry on OJ 287 could allow us to accurately locate its jet apex and
activity boundary, align its restless jet structure over decades without
significant systematic bias, and probe various astrophysical scenarios.Comment: 10 pages, 3 figures, 2 tables, accepted for publication in
Astrophysical Journal Letter
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Early Holocene monsoon instability and climatic optimum recorded by Chinese stalagmites
The timing and duration of the Holocene East Asian summer monsoon (EASM) maximum and the interpretation of Chinese stalagmite δ18O records have long been disputed. Notably, interpretations of Holocene EASM variations are frequently based on a single record or study area and are often contradictory. In this study, we conducted stable isotope analyses of four Holocene stalagmites from Chongqing, southwest China. The results reveal differences in the timing of the Holocene EASM maximum and to try to resolve the inconsistency we analyzed and statistically integrated a total of 16 Holocene stalagmite records from 14 caves in the EASM region. The resulting synthesized Holocene stalagmite δ18O (δ18Osyn) record is in agreement with other EASM records and confirms that stalagmite δ18O records are a valid indicator of EASM intensity, rather of local precipitation amount. The δ18Osyn record shows that the EASM intensified rapidly from the onset of the early Holocene; notably, however, there were distinct EASM oscillations in the early Holocene, consisting of three abrupt millennial-scale events. This indicates that, contrary to several previous interpretations, the early Holocene EASM was unstable. Subsequently, during 8–6 kyr BP, the EASM was relatively stable and strong, with the strongest monsoon occurring during 8–7 kyr BP. This evidence of a stable and strong mid-Holocene EASM in eastern China is in accord with the classical view of a mid-Holocene Optimum in China
Functional annotation of proteomic data from chicken heterophils and macrophages induced by carbon nanotube exposure
With the expanding applications of carbon nanotubes (CNT) in biomedicine and agriculture, questions about the toxicity and biocompatibility of CNT in humans and domestic animals are becoming matters of serious concern. This study used proteomic methods to profile gene expression in chicken macrophages and heterophils in response to CNT exposure. Two-dimensional gel electrophoresis identified 12 proteins in macrophages and 15 in heterophils, with differential expression patterns in response to CNT co-incubation (0, 1, 10, and 100 µg/mL of CNT for 6 h) (p < 0.05). Gene ontology analysis showed that most of the differentially expressed proteins are associated with protein interactions, cellular metabolic processes, and cell mobility, suggesting activation of innate immune functions. Western blot analysis with heat shock protein 70, high mobility group protein, and peptidylprolyl isomerase A confirmed the alterations of the profiled proteins. The functional annotations were further confirmed by effective cell migration, promoted interleukin-1β secretion, and more cell death in both macrophages and heterophils exposed to CNT (p < 0.05). In conclusion, results of this study suggest that CNT exposure affects protein expression, leading to activation of macrophages and heterophils, resulting in altered cytoskeleton remodeling, cell migration, and cytokine production, and thereby mediates tissue immune responses
Speeding Up RSA Encryption Using GPU Parallelization
Abstract-Due to the ever-increasing computing capability of high performance computers today, in order to protect encrypted data from being cracked, the bit number used in RSA, a common and practicable public-key cryptosystem, is also getting longer, resulting in increasing operation time spent in executing the RSA algorithm. We also note that while the development of CPU has reached limits, the graphics processing unit (GPU), a highly parallel programmable processor, has become an integral part of today's mainstream computing systems. Therefore, it is a savvy choice to take advantage of GPU computing to accelerate computation of the RSA algorithm and enhance its applicability as well. After analyzing the RSA algorithm, we find that big number operations consume most parts of computing resources. As the benefit acquired from combining Montgomery with GPU-based parallel methods is not high enough, we further introduce the Fourier transform and Newton's method to design a new parallel algorithm to accelerate the computation of big numbers
Square Key Matrix Management Scheme in Wireless Sensor Networks
In this paper we propose a symmetric cryptographic approach named Square Key Matrix Management Scheme (SKMaS) in which a sensor node named Key Distribution Server (KDS) is responsible for the security of key management. When the system starts up, the KDS sends its individual key and two sets of keys to sensor nodes. With the IDs, any two valid sensor nodes, e.g. i and j, can individually identify the corresponding communication keys (CKs) to derive a dynamic shared key (DSK) for encrypting/decrypting messages transmitted between them. When i leaves the underlying network, the CKs and the individually keys currently utilized by i can be reused by a newly joining sensor, e.g. h. However, when h joins the network, if no such previously-used IDs are available, h will be given a new ID, CKs and the individually key by the KDS. The KDS encrypts the CKs, with which an existing node q can communicate with h, with individual key so that only q rather than h can correctly decrypt the CKs. The lemmas and security analyses provided in this paper prove that the proposed system can protect at least three common attacks
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