به نام خدا
Title: A Cognitive Link Adaptation Strategy with Differentiated Responses on Wi-Fi System-on-Chip
Authors: Taeyoung Lee, Myounghwan Lee, Jaeeun Kang, Kyungik Cho, ChilYoul Hacky Yang, and Scott Seongwook Lee
Abstract: The dynamic change of wireless channel condition causes poor Wi-Fi quality of service. To cope with the channel variation of wireless communication, the essential strategy for the physical layer with multi-rate capability is the link adaptation. However, because definite guidelines for rate changes do not exist, most link adaptation algorithms can misleadingly increase transmission rates. Therefore, we propose a cognitive link adaptation scheme, sensing link adaptation urgency and responding with differentiated rate control such as the long-term rate adaptation with a short-term rate drop. To evaluate the proposed scheme, we implement the link adaptation scheme on Wi-Fi System-on-Chip, applying the optimal HW/SW partitioning technique to reduce the SW processing delay from heavy operating calculation for the algorithm. The experiment shows that the proposed algorithm increases the packet arrival rate in a real Wi-Fi environment by reducing transmission failure due to wrong rate changes.
Publish Year: 2013
Published in: CCNC - IEEE
Number of Pages: 6
موضوع: شبکه های بی سیم
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: The alpha parallelogram predictor: A lossless compression method for motion capture data
Authors: Pengjie Wang , Zhigeng Pan d,a , Mingmin Zhang a, , Rynson WH Lau c , Haiyu Song
Abstract: Motion capture data in an uncompressed form can be expensive to store, and slow to load and transmit. Current compression methods for motion capture data are primarily lossy and cause distortions in the motion data. In this paper, we present a lossless compression algorithm for motion capture data. First, we propose a novel Alpha Parallelogram Predictor (APP) to estimate the DOF (degree of freedom) of each child joint from those of its immediate neighbors and parents that have already been processed. The prediction parameter of the predictor, which is referred to as the alpha parameter, is adaptively chosen from a care- fully designed lookup table. Second, we divide the predicted and actual values into three components: sign, exponent and mantissa. We then compress their corrections separately with context-based arithmetic coding. Compared with other lossless compression methods, our approach can achieve a higher compression ratio with a comparable compression time. It can be used in situations where lossy compression is not preferred.
Publish Year: 2013
Published in: Information Sciences - Science Direct
Number of Pages: 10
موضوع: فشرده سازی داده ها
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Quotients and weakly algebraic sets in pseudoeffect algebras
Authors: HaiYang Li JiGen Peng
Abstract: In the paper, we show that the quotient ½E I of alattice-ordered pseudoeffect algebra E with respect to anormal weak Riesz ideal I is linearly ordered if and only ifI is a prime normal weak Riesz ideal, and ½E I is a repre-sentable pseudo MV-algebra if and only if I is an inter-section of prime normal weak Riesz ideals. Moreover, weintroduce the concept of weakly algebraic sets in pseudo-effect algebras, discuss the characterizations of weaklyalgebraic sets and show that weakly algebraic sets inpseudoeffect algebra E are in a one-to-one correspondencewith normal weak Riesz ideals in pseudoeffect algebra E:
Publish Year: 2012
Published in: Soft Computing - Springer
Number of Pages: 8
موضوع: جبر
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Concept-Based Readability of Web Services Descriptions
Authors: Pananya Sripairojthikoon, Twittie Senivongse
Abstract: Web Services is a technology for building distributed software applications that are built upon a set of information and communication standards. Among those standards is the Web Services Description Language (WSDL) which is an XML-based language for describing service descriptions. Service providers will publish WSDL documents of their Web services so that service consumers can learn about service capability and how to interface with the services. Since WSDL documents are the primary source of service information, readability of WSDL documents is of concern to service providers, i.e. service descriptions should be understood with ease by service consumers. Providing highly readable service descriptions can then be used as a strategy to attract service consumers. However, given highly readable information in the WSDL documents, competitors are able to learn know-how and can copy the design to offer competing services. Security attacks such as information espionage, client impersonation, command injection, and denial of service are also possible since attackers can learn about exchanged data and invocation patterns from WSDL documents. While readability of service descriptions makes Web services discoverable, it contributes to service vulnerability too. Service designers therefore should consider this trade-off when designing service descriptions. Currently there is no readability measurement for WSDL documents. We propose an approach to such measurement so that service designers can determine if readability is too low or too high with regard to service discoverability, service imitation, and service attack issues, and then can consider increasing or lowering service description readability accordingly. Our readability measurement is based on the concepts or terms in service domain knowledge. Given a WSDL document as a service description, readability is defined in terms of the use of difficult words in the description and the use of words that are key concepts in the service domain. As an example, we measure readability of the WSDL document of public Web services, and outline a method to lower or increase readability.
Publish Year: 2013
Published in: ICACT - IEEE
Number of Pages: 6
موضوع: وب سرویس
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: A method for the coating of a polymer inclusion membrane with a monolayer of silver nanoparticles
Authors: Ya Ya N Bonggotgetsakul, Robert W Cattrall, Spas D Kolev
Abstract: The preparation of silver nanoparticles (AgNPs) is described using a polymer inclusion membrane (PIM) consisting of 45% (m/m) di-(2-ethylhexyl)phosphoric acid (D2EHPA) and 55% (m/m) poly(vinyl chloride) (PVC) as a template. The Ag(I) ion was ?rstly extracted into the membrane via cation-exchange and then subsequently reduced with NaBH , trisodium citrate, citric acid, or L-ascorbic acid to form AgNPs. The most effective reducing agent was found to be L-ascorbic acid which at pH 2.0 formed a uniform monolayer of AgNPs of an average size of 360 nm on the surface of the PIM. Citric acid also produced AgNPs but these were embedded in the bulk of the membrane and did not provide a good surface coverage. NaBH and trisodium citrate, on the other hand, gave rise to the formation of black silver oxide on the membrane surface. Factors such as the membrane loading with Ag(I), PIM composition, reduction time, temperature and shaking time were found to have a significant influence on the surface coverage and size of the AgNPs.
Publish Year: 2013
Published in: Journal of Membrane Science - Science Direct
Number of Pages: 8
موضوع: مهندسی شیمی
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان