• Journal of Information Processing Systems
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• v.7 no.4
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• pp.691-706
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• 2011

Since security and privacy problems in RFID systems have attracted much attention, numerous RFID authentication protocols have been suggested. One of the various design approaches is to use light-weight logics such as bitwise Boolean operations and addition modulo $2^m$ between m-bits words. Because these operations can be implemented in a small chip area, that is the major requirement in RFID protocols, a series of protocols have been suggested conforming to this approach. In this paper, we present new attacks on these lightweight RFID authentication protocols by using the Gr$\ddot{o}$bner basis. Our attacks are superior to previous ones for the following reasons: since we do not use the specific characteristics of target protocols, they are generally applicable to various ones. Furthermore, they are so powerful that we can recover almost all secret information of the protocols. For concrete examples, we show that almost all secret variables of six RFID protocols, LMAP, $M^2AP$, EMAP, SASI, Lo et al.'s protocol, and Lee et al.'s protocol, can be recovered within a few seconds on a single PC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.1107-1115
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• 1997

In this paper, we propose an error concealment method to recovre damaged block-based image coding schemes. Channel errors during transmission of image data such as bit errors or cell loss result in damaged image blocks in the reconstructed images. To recover damaged blocks is to estimate them using the correctly received or undamaged neighborhood information. In the proposed method, an overcomplete basis for a large block containing a damaged block at its center is introduced and damaged blocks are recovered by sequentially projecting the known neighborhood information onto the overcomplete basis function. Computer simulations show that the proposed algorithm outperforms the conventional method in subjectie recovery qualities as well as objective ones.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.108-110
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• 2000

The aim of this paper is to investigate the effect of Al and Ti on microstructure of Fe-Cr-Al alloy systems for applying electrical resistance wires of electrical furnace. From the preliminary study, the amount of recovered addition elements increased in the case of both vacuum and Ar-atmosphere melting than that in the case of air-atmosphere melting. Also, optimum Cr content for good performance at high temperature was approximately 24wt% from the observation of microstucture. The precipitates of Fe-Cr, Al-Cr and Al phases were observed, adding Al and Ti. Especially, Sharp rectangular shapes of precipitates were observed with increasing amount of Ti.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.131-133
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• 1995

Inductive high-Tc superconducting fault current limiter using YBCO superconducting ring in the secondary part has many advantages in power networks. It is based on the superconducting to normal transition and this paper describes its operational characteristics and experimental results, especially focused on the harmonic component analysis and recovery time. We fabricated and tested it under various conditions for the analysis of transient fault characteristics. And for the analysis of harmonics we used FFT methods. The superconducting ring was quenched in 240Arms and fault current was effectively limited to the lower current level. In addition, it was fast recovered when the fault condition was removed and after fault the system had odd harmonics.

• Journal of Korean Society for Quality Management
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• v.22 no.3
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• pp.142-151
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• 1994

In a hospital, there are many clinical departments. In general, the hospital management often uses the index of cure rate (i.e. the rate of patients recovered by the cure of this hospital) to evaluate the medical quality of each clinical department. But, since the cure rate varies significantly with the rate of patient with severe disease, the evaluation by cure rate is unreasonable and incomplete. This paper proposes a new evaluation method called the cause-selecting evaluation method proposed by Prof. Gongxu Zhang (1990). Besides, this method can also be used to diagnose the abnormality of cure rate. The practical case studies check with the theory very well.

• Korean Journal of Materials Research
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• v.17 no.10
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• pp.544-547
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• 2007

Human teeth were scratched by the abrasive paper, dropping in hydroxyapatite solution during 1, 2, 3, 4 months. We studied teeth surface change with SEM each months. After 1 months treatment the surface appeared the change. Because of the hydroxyapatite ion exchange mechanism. The scratched surface was recovered by the hydroxyapatite. The results of EDS showed that $Ca^{2+}$ ion and $PO_4^{3-}$ ion were removed from hydroxyapatite solution to scratched teeth surface.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.621-625
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• 2019

There is often the risk of confusing pollen grains with helminth eggs from archaeological sites. Thousands to millions of pollen grains can be recovered from archaeological burial sediments that represent past ritual, medication and environment. Some pollen grain types can be similar to parasite eggs. Such a confusion is represented by the diagnosis of enterobiasis in ancient Iran. The authors of this study confused a joint-pine (Ephedra spp.) pollen grain with a pinworm egg. This paper describes the specific Ephedra pollen morphology that can be confused with pinworm eggs.

• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.15-22
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• 2011

In this study, liquid with carbonized artemisia was developed for the first time that can be used as food additives and outside medicinal agents by burning artemisia species such as Artemisia dubia wall, Artemisia capillaris Thunb, Artemisia montana (Nakai) Pamp), Artemisia keiskeana Miq, Leonurus Japonicus Houtt. etc. In addition, edibility of recovered liquid with carbonized artemisia was verified by comparing the contents according to each ingredient with common refined pyroligneous liquid through the analysis of 9 kinds of organic acid by the species of artemisia, methanol and ethanol. Besides, the result of antimicrobial activities on six kinds of food spoilage and food poisoning bacteria observed by paper disc method for liquid with carbonized artemisia indicated that those two liquids showed strong antimicrobial. At the concentration of 1.5 mg/disc, clear zone for S. sonnei and S. aureus, L. monocytogenes was 13~16 mm, and they showed stronger antimicrobial activities than other strain.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.690-696
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• 2003

This paper presents the heat recovery performance of water fluidized-bed heat exchanger. Temperature and humidity ratio of waste gas are considered as important parameters in this study. Therefore, the heat recovery rate through water fluidized-bed heat exchanger for exhaust gases with various temperatures and humidity ratios can be estimated from the results of this study. Mass flow ratio (the ratio of mass flow rate of water to that of gas) and temperature of inlet water are also considered as important operating variables. Increase of heat recovery rate can be obtained through either high mass flow ratio or low temperature of inlet water with resultant low recovered temperature. The heat recovery performance with the mass flow ratio of about up to 10 has been investigated. The effect of number of stages of water fluidized-bed on the heat recovery performance has been also examined in this study.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.247-253
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• 2021

The outbreak of the deadly virus COVID-19 is said to infect 17.3Cr people around the globe since 2019. This outbreak is continuously affecting a lot of new people till this day and, most of it is said to under control. However, vaccines introduced around the world can help mitigate the risk of the virus. Apart from medical professionals, prediction models are also said to combinedly help predict the risk of infection based on given datasets. This paper is based on publication of a machine learning approach using regression models to predict the output based on dataset which have indictors grouped based on active, tested, recovered and critical cases along with regions and cities covering most of it from Dubai. Hence, the active cases are tested based on the other indicators and other attributes. The coefficient of the determination (r²) is 0.96, which is considered promising. This model can be used as an frame work, among others, to predict the resources related to the dangerous outbreak.