• ETRI Journal
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• v.22 no.4
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• pp.25-31
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• 2000

Design of secure and efficient public-key encryption schemes under weaker computational assumptions has been regarded as an important and challenging task. As far as ElGamal-type encryption schemes are concerned, some variants of the original ElGamal encryption scheme based on weaker computational assumption have been proposed: Although security of the ElGamal variant of Fujisaki-Okamoto public -key encryption scheme and Cramer and Shoup's encryption scheme is based on the Decisional Diffie-Hellman Assumption (DDH-A), security of the recent Pointcheval's ElGamal encryption variant is based on the Computational Diffie-Hellman Assumption (CDH-A), which is known to be weaker than DDH-A. In this paper, we propose new ElGamal encryption variants whose security is based on CDH-A and the Elliptic Curve Computational Diffie-Hellman Assumption (EC-CDH-A). Also, we show that the proposed variants are secure against the adaptive chosen-ciphertext attack in the random oracle model. An important feature of the proposed variants is length-efficiency which provides shorter ciphertexts than those of other schemes.

• Steel and Composite Structures
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• v.3 no.4
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• pp.277-287
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• 2003

The low boundary of load carrying capacity of the elastic-plastic spatial grid structures depend on numerous values and their variability assumed in designing process. Analysed influence all this values in searching for optimal variant of the structure lead to too great problem even taking into consideration actual computational power we have in disposal. Therefore one can take only a few values which have greatest influence on the optimal choice. In optimal analysis of the elastic-plastic spatial grid structures the previously proposed method with subsequent modification (Karczewski 1980), (Karczewski, Barszcz and Donten 1996), (Karczewski and Donten 2001) as well as computer program which was worked out by Donten K. to make possible practical utilisation this method was employed. The paper deal with evaluation of influence dimensions of particular values for choice of optimal variant of the structure. One among this values is distribution of the struts in the structure.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.497-500
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• 2007

Data structure was designed not only to estimate LCC but also to analyze time-variant reliability index of plate girder bridges. Information model for data structure was categorized into cost information, cost variable information, user cost information, and reliability analysis information according to the characteristic of data. EXPRESS language of STEP was adopted to describe the data structure for the electronic representation of LCC information. The suitability of the developed data structure was verified by estimating LCC and analyzing time-variant reliability index of a plate girder bridge considering corrosion on the basis of the constructed test database.

• Advances in pediatric surgery
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• v.1 no.2
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• pp.190-194
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• 1995

Diphallus is a rare congenital anomaly and is frequently associated with duplication of the urinary tract and rectosigmoid, and commonly associated with vertebral anomalies. Remzi reported less than 100 cases of duplication of all or a portion of the penis, but about 10 cases of complete diphallus with exstrophy of cloaca was reported, and a case of complete diphallus associated with hindgut duplication was reported, and complete diphallus with displacement of bladder associated hindgut duplication and imperforate anus was not reported in Korea. We experienced a case of the complete diphallus associated with displacement of bladder, hindgut duplication, and imperforate anus as a variant of cloacal exstrophy. A review of published cases suggests that this may be the first example of a complete diphallus with displacement of bladder coexisting with the hindgut duplication and imperforate anus.

• Agricultural and Biosystems Engineering
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• v.1 no.1
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• pp.38-42
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• 2000

Though the freshness for agricultural products is an important factor related to their quality management, this terminology is being used restrictedly because it is very subjective. In this study, a dimensionless index which had the span of the maximum of 1 through the minimum of 0 was proposed to describe freshness of the product with time-variant quality and was applied to Tsugaru and Fuji apples. First, the compressive properties having the linearity in their change regarding time elapsed after harvest were selected. For Tsugaru apple, bio-yield and rupture forces had high correlation with time while for Fuji, bio-yield and rupture deformations had high correlations. When the slope, or ratio of force to deformation, was considered, the effect of cultivar could be neglected. When the linearly time-variant compressive properties for Tsugaru and Fuji apples were involved in the freshness indices, they described well freshness of apples. Also, the freshness decay constant depicted a characteristic which related to freshness decay rate. Therefore, the freshness index can be utilized to manage the quality during storage and distribution of apples.

• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.471-474
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• 2007

In this paper, we propose a variant of Diffie-Hellman key exchange protocol to provide pre-computable session key and to give another version of Diffie-Hellman key exchange protocol that might be useful in designing more sophisticated cryptographic protocols. We prove the security of the key exchange protocol by reducing DH key exchange protocol to ours.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.138-146
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• 2010

On wind turbine generators, the speed and volume of the wind affect the turbine angle speed which finally determines the output level of the electric power. However it is very difficult to forecast correctly the future power output and quality based on previous fixed sampling methods. This paper proposes a variable sampling method based on Buneman frequency estimation algorithm to reflect the variations of the frequency and amplitude on wind power outputs. The proposed method is also verified through the performance test by comparing with the results from previous fixed sampling methods and the real measurement data.

• Journal of Chest Surgery
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• v.13 no.2
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• pp.118-124
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• 1980

A double aorto-coronary bypass procedure performed in 2 cases, one with a Prinzmetal`s variant angina and the other with an unstable angina, is presented. The patient with a Prinzmetal`s angina who had a high-grade obstruction of the left anterior descending and the right coronary system showed a marked postoperative improvement with complete disappearance of anginal pain. The other patient with unstable angina had obstruction of the left anterior descending as well as a marginal branch of the left circumflex artery. Following bypass of these vessels, the patient did well during the immediate postoperative period. However, he developed hypotension in the recovery room and died 6 hours postoperatively, in spite of an intensive effort at resuscitation. The most likely cause of death in this patient is a myocardial infarction.

• The Korean Journal of Cytopathology
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• v.17 no.2
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• pp.148-152
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• 2006

Due to its nuclear pleomorphism, knowledge regarding the cytological findings of cerebellar hemangioblastoma can lead to misdiagnosis when using squash specimens, which in other circumstances serves as a useful adjunct in the diagnosis of brain tumors on frozen section. We recently experienced the cytological findings of a cellular variant of cerebellar hemangioblastoma in a 51-year-old man. Squash specimens revealed scattered single tumor cells, with pleomorphic nuclei and cytoplasmic vacuoles, on a hemorrhagic background. The cellular clusters were composed of spindle-shaped endothelial cellsin addition to densely clustered stromal cells. Intranuclear inclusions were frequently seen. The nuclear pleomorphism, bubbly cytoplasmic vacuoles and presence of intranuclear inclusions, seen in the squash specimen, may increase the difficulty of frozen section diagnosis of cerebellar hemangioblastoma. Awareness of the cytologicalfindings of hemangioblastoma is needed to avoid the pitfalls in the intraoperative diagnosis of cerebellar hemangioblastomas.

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.72-81
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• 2001

An adaptive channel estimation technique for OFDM-based DTV receivers is proposed using a new mobility estimator. Sample mean techniques for channel estimation have displayed good performance in slow fading channels, because averaging reduces noise In channel estimation operation. This paper suggests an algorithm which selects the optimal number of symbols within which the sample mean of consecutive pilot data can be obtained. The designed mobility estimator determines the optimal number by comparing mobility variance and estimated noise valiance. The algorithm using the mobility estimator obtains an optimal channel function under time-invariant or time-variant multipath fading channels, thereby making the best BER performance.