Wyniki wyszukiwania - Biblioteka Nauki

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An Efficient Decoding of Goppa Codes for the McEliece Cryptosystem

100%

Lim S. , Lee H.-S. , Choi M.

Fundamenta Informaticae

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2014

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tom Vol. 133, nr 4

387--397

EN

The McEliece cryptosystem is defined using a Goppa code, and decoding the Goppa code is a crucial step of its decryption. Patterson’s decoding algorithm is the best known algorithm for decoding Goppa codes. Currently, the most efficient implementation of Patterson’s algorithm uses a precomputation. In this paper, we modify Patterson’s decoding algorithm so that one can remove the precomputation part while sustaining the best efficiency. Precomputations yield additional storage requirement to store the precomputed value which increases as the security level increases in McEliece cryptosystem. In the original decoding algorithm of Patterson, computing square root in a quotient field of polynomial ring over a finite field is necessary. In our modification, the computations are involved only in the arithmetics of polynomial ring over a finite field, not in the quotient field. This achieves better efficiency because one can remove polynomial reductions in the computations of quotient field.

2

A study on superplastic forming of multiple sheet with integral stiffeners

100%

Lee H.-S. , Yoon J.-H. , Yoo J.-T. , Choi J.-U.

Inżynieria Materiałowa

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2014

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tom Vol. 35, nr 2

166--170

EN

Blow molding process is one of the common manufacturing processes in plastic and glass industry. The advantages include low cost of the tool and ability to mold complex part. In metallic system, a similar process like superplastic forming has been widely used in aerospace industry, since it is possible to fabricate very thin part and hence lightweight structure. The present study demonstrates superplastic blow forming process with IN718 and titanium and aerospace components with a complex shape which were successfully manufactured. These metals have been used for high temperature application like lightweight propulsion systems. It is interesting to notice high value of strain rate sensitivity obtained for titanium alloy, while this for IN718 was relatively low at the forming temperature. The result shows that the developed technology to design high temperature superplastic forming by the finite element method can be applied for nearly net shape forming 2-sheet, 3-sheet and 4-sheet stiffened panels for lightweight component of aerospace structure.

PL

Proces formowania przez nadmuchiwanie jest jednym z najpowszechniejszych procesów w przemyśle tworzyw sztucznych i szkła. Zalety tego procesu polegają na niskich kosztach narzędzi oraz zdolnościach do formowania złożonych części. W systemach metalicznych, podobny proces – formowanie nadplastyczne jest szeroko stosowane w przemyśle lotniczym, ponieważ umożliwia otrzymywanie bardzo cienkich grubości materiału a więc struktur lekkiej konstrukcji. Przedstawione studium demonstruje nadplastyczne formowanie przez nadmuchiwanie z wykorzystaniem IN178, tytanu oraz otrzymanie w ten sposób lotniczych komponentów o złożonym kształcie. Te metale są wykorzystane w aplikacjach wysokotemperaturowych takich jak lekkie systemy napędowe. Należy zwrócić uwagę na dużą wrażliwość na szybkość odkształcenia stopów tytanu, podczas gdy dla IN718 jest ona relatywnie niska w temperaturze formowania. Wyniki te pokazują, że rozwinięta technologia procesu projektowania wysokotemperaturowego formowania nadplastycznego za pomocą MES może być stosowana w postaci 2, 3, 4 arkuszowych paneli usztywniających dla lekkich komponentów przemysłu lotniczego.

3

Seroprevalence of Toxoplasma gondii and Neospora caninum in dogs from Korea

75%

Nguyen T. T.-D. , Choe S.-E. , Byun J.-W. , Koh H.-B. , Lee H.-S. , Kang S.-W.

Acta Parasitologica

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2012

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tom 57

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nr 1

EN

Toxoplasma gondii and Neospora caninum are closely related protozoan parasites, they share many common hosts, and can cause neurological diseases in dogs. Dogs can have close contacts with humans and livestock and therefore they can act as reservoirs of these parasites. The aim of this study was to survey the seroprevalence of antibodies against T. gondii and N. caninum and their co-infection rate in dogs in Korea. In total, sera from 553 domestic dogs were collected from different breeds, sexes, and ages of dogs from nine provinces across the country of Korea during 2006 and 2007. The presence of antibodies against T. gondii and N. caninum was analyzed using the latex agglutination test (LAT) with a cut-off value of 1:32, and the indirect fluorescent antibody test (IFAT) using a serum titer of 1:100. In the total dog population, 71 (12.8%) dogs were positive for anti-T. gondii antibodies and only 20 (3.6%) were positive for anti-N. caninum antibodies. Relatively higher seropositive frequencies of antibodies against T. gondii (20.1%) and N. caninum (4.9%) were detected in the dog population from the Gyeonggi. A higher proportion of animals seropositive for anti-T. gondii antibodies was found in stray dog populations as compared to household dog populations: 18.5% (59/319) vs 5.1% (12/234), respectively. The Chi-square tests revealed significant differences in the seropositive frequencies of antibodies against T. gondii between stray and household dogs in the total population (p<0.0001), and in dogs from the Gyeonggi (p<0.01). No significant differences were observed for the presence of antibodies against T. gondii or N. caninum when compared across the sex or age (p>0.05). The first serological survey on antibodies against both T. gondii and N. caninum parasites across the entire country showed that co-infection was not common in these canine populations with a seropositive level of 0.72%. The significantly higher positive frequency of T. gondii antibodies in stray dogs in both, Gyeonggi and in the total dog populations suggests that further investigation on the seroprevalence of parasites should focus on stray dogs.