• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권1호
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• pp.344-365
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• 2020

Providing security has been always on priority in all areas of computing and communication, and for the systems that are low on computing power, implementing appropriate and efficient security mechanism has been a continuous challenge for the researchers. Radio Frequency Identification (RFID) system is such an environment, which requires the design and implementation of efficient security mechanism. Earlier, the security protocols for RFID based on hash functions and symmetric key cryptography have been proposed. But, due to high strength and requirement of less key size in elliptic curve cryptography, the focus of researchers has been on designing efficient security protocol for RFID based on elliptic curves. In this paper, an efficient elliptic curve signcryption based security protocol for RFID has been proposed, which provides mutual authentication, confidentiality, non-repudiation, integrity, availability, forward security, anonymity, and scalability. Moreover, the proposed protocol successfully provides resistance from replay attack, impersonation attack, location tracking attack, de-synchronization attack, denial of service attack, man-in-the-middle attack, cloning attack, and key-compromise attack. Results have revealed that the proposed protocol is efficient than the other related protocols as it takes less computational time and storage cost, especially for the tag, making it ideal to be used for RFID systems.

• Parasites, Hosts and Diseases
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• 제51권4호
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• pp.427-432
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• 2013

A new trichostome ciliate, Balantidium honghuensis n. sp., was isolated from the recta of Rana nigromaculata and R. limnocharis during parasite surveys in Honghu Lake, Hubei Province, central China in summmer of 2010 and 2011. Its detailed morphometric characters based on LM and SEM studies were described herein. The organism is oval in shape and thickly ciliated. The vestibulum is "V" shaped and occupies about 1/3 to 2/5 of the body length. The vestibular and nearby regions possess strong peripheral fibers which form a marked axial fiber about the cytopharynx. More than 10 contractile vacuoles are distributed along the periphery of the latter body. Comparisions were made between this new species and B. sinensis Nie, 1935. They were discriminated from each other in terms of general body forms, body size, and vestibulum shapes. Besides, special attention was paid to its high-speed daughter swarmers which we believed to be the infective stage of B. honghuensis. Possible infection routes of anura amphibian balantidia were discussed.

• ETRI Journal
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• 제38권3호
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• pp.560-567
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• 2016

To solve the problem of parameter optimization in image sensor-based visible light positioning systems, theoretical limits for both the location and the azimuth angle of the image sensor receiver (ISR) are calculated. In the case of a typical indoor scenario, maximum likelihood estimations for both the location and the azimuth angle of the ISR are first deduced. The Cramer-Rao Lower Bound (CRLB) is then derived, under the condition that the observation values of the image points are affected by white Gaussian noise. For typical parameters of LEDs and image sensors, simulation results show that accurate estimates for both the location and azimuth angle can be achieved, with positioning errors usually on the order of centimeters and azimuth angle errors being less than $1^{\circ}$. The estimation accuracy depends on the focal length of the lens and on the pixel size and frame rate of the ISR, as well as on the number of transmitters used.

• Computers and Concrete
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• 제22권5호
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• pp.469-479
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• 2018

The Brazilian tensile strength of concrete samples is a key parameter in fracture mechanics since it may significantly change the quality of concrete materials and their mechanical behaviors. It is well known that porosity is one of the most often used physical indices to predict concrete mechanical properties. In the present work the influence of porosity shape on concrete tensile strength characteristics is studied, using a bonded particle model. Firstly numerical model was calibrated by Brazilian experimental results and uniaxial test out puts. Secondly, Brazilian models consisting various pore shapes were simulated and numerically tested at a constant speed of 0.016 mm/s. The results show that pore shape has important effects on the failure pattern. It is shown that the pore shape may play an important role in the cracks initiation and propagation during the loading process which in turn influence on the tensile strength of the concrete samples. It has also been shown that the pore size mainly affects the ratio of uniaxial compressive strength to that of the tensile one in the simulated material samples.

• Archives of design research
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• 제15권1호
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• pp.81-92
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• 2002

Through network draft, it′s possible to describe curve draft with main motive in a lobby loom and to fulfill draft design more conveniently thanks to the development of computer device. Network draft was introduced by Alice Schlein, who is an American weaving artist, and I had ever published research paper on "The unfolding and development of network draft using computer dobby system" . The purpose of the next study was to develop the design of network draft while do make a design network draft in a dobby loom with 16 shafts, and could reach follow conclusion as a result of designing a variety of drafts. The initial of 4-end in a loom with 16 shafts was a basic condition to describe more perfect shape in comparison with draft in 8 shafts through the development of network. The development of draft line was essential to deride the pattern of fabric, and the pattern of draft is decided according to selecting key peg plan. Thereby, could get a variety of draft patterns derive from mix key peg plan with initial selected by developing the kind of draft line and applying diverse key peg plan. As for the variation and diversification of draft line, the shape of patters varied depending col the curve extent and connectivity of draft line and the size of curve. The pattern of network draft can be changed infinitely by free round curve of draft line. In addition, a variety of draft designs shall be developed by increasing the number of shaft, enlarging the scale of draft line, and developing more creative draft line.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2407-2426
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• 2016

A group signature scheme allows any member to sign on behalf of a group. It is applied to practical distributed security communication environments, such as privacy-preserving, data mining. In particular, the excellent features of group signatures, including membership joining and revocation, anonymity, traceability, non-frameability and controllable linkability, make group signature scheme more attractive. Among these features, non-frameability can guarantee that a member's signature cannot be forged by any other (including issuer), and controllable linkability supports to confirm whether or not two group signatures are created by the same signer while preserving anonymity. Until now, only Hwang et al.'s group schemes (proposed in 2013 and 2015) can support all of these features. In this paper, we present a new dynamic group signature scheme which can achieve all of the above excellent features. Compared with their schemes, our scheme has the following advantages. Firstly, our scheme achieves more efficient membership revocation, signing and verifying. The cost of update key in our scheme is two-thirds of them. Secondly, the tracing algorithm is simpler, since the signer can be determined without the judging step. Furthermore, in our scheme, the size of group public key and member's private key are shorter. Lastly, we also prove security features of our scheme, such as anonymity, traceability, non-frameability, under a random oracle model.

• Nuclear Engineering and Technology
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• 제47권3호
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• pp.323-331
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• 2015

Zirconium alloys are widely used in nuclear reactors as structural materials. During the operation, they are exposed to fast neutrons. Ion irradiation is used to simulate the damage introduced by neutron irradiation. In this article, we briefly review the neutron irradiation damage of zirconium alloys, then summarize the effect of ion irradiation on microstructural evolution, mechanical and corrosion properties, and their relationships. The microstructure components consist of dislocation loops, second phase precipitates, and gas bubbles. The microstructure parameters are also included such as domain size and microstrain determined by X-ray diffraction and the S-parameter determined by positron annihilation. Understanding the relationships of microstructure and properties is necessary for developing new advanced materials with higher irradiation tolerance.

• Journal of Power Electronics
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• 제16권3호
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• pp.1200-1208
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• 2016

Planar electromagnetic interference (EMI) filter has significant engineering significance to power electronic system integration and miniaturization. However, the value of differential mode capacitance cannot meet the demand of noise suppression because of the size limit of ceramics. In this case, the EMI filter of novel multilayers is recommended to address this issue. A novel integrated structure of EMI filter based on multilayer ceramic is proposed in this study. The inductance and capacitance of the new structure can be designed separately, which is an advantage in manufacturing. Insertion loss is measured more closely to the actual situation in this study, which is different from the condition where source and load impedances are both 50 Ω. In the process of designing a novel EMI filter, noise impedance is considered. Moreover, the prototype is created and applied to a small switching power supply, which verifies the effectiveness of the developed EMI filter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.872-875
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• 2005

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication, and can provides the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2(Privacy Key Management) protocol for authorization and key exchange between a MSS(Mobile Subscriber Station) and a BS(Base Station). This paper first reviews and studies overall security architecture of TTA HPi standard and IEEE 802.16e which supports mobility based on WMAN(Wireless Metropolitan Area Network) standard(IEEE 802.16)

• Journal of Power Electronics
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• 제14권4호
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• pp.806-813
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• 2014

Planar electromagnetic interference (EMI) filters are widely used to restrain the conducted EMI of switching power supplies. Such filters are characterized by small size, low parasitic parameters, and better high-frequency performance than the passive discrete EMI filter. However, EMI filter performance cannot be exactly predicted by using existing methods. Therefore, this paper proposes a method to use scattering parameters (S-parameters) for the measurement of EMI filter performance. A planar EMI filter sample is established. From this sample, the relationship between S-parameters and insertion gain (IG) of EMI filter is derived. To determine the IG under different impedances, the EMI filter is theoretically calculated and practically measured. The differential structure of the near-field coupling model is also deduced, and the IG is calculated under standard impedance conditions. The calculated results and actual measurements are compared to verify the feasibility of the theory.