• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1121-1125
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• 2010

This paper proposes a Wikipedia-based feedback method for in-depth blog distillation whose goal is to find blogs that represent in-depth thoughts or analysis on a given query. The proposed method uses Wikipedia articles which are relevant to the query. TREC Blogs08 collection which is a large-scale blog corpus and English Wikipedia dump were used for experiments, The proposed method significantly increased the retrieval performance including MAP over the conventional post based feedback method.

• The KIPS Transactions:PartB
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• v.19B no.1
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• pp.37-42
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• 2012

The pseudo relevance feedback suggests that frequent words at the top documents are related to initial query. However, the main drawback associated with the term frequency method is the fact that it relies on feature independence, and disregards any dependencies that may exist between words in the text. In this paper, we propose query expansion based on word graph using term proximity. It supplements term frequency method. On TREC WT10g test collection, experimental results in MAP(Mean Average Precision) show that the proposed method achieved 6.4% improvement over language model.

• ETRI Journal
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• v.21 no.1
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• pp.28-39
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• 1999

Koblitz has suggested to use "anomalous" elliptic curves defined over ${\mathbb{F}}_2$, which are non-supersingular and allow or efficient multiplication of a point by and integer, For these curves, Meier and Staffelbach gave a method to find a polynomial of the Frobenius map corresponding to a given multiplier. Muller generalized their method to arbitrary non-supersingular elliptic curves defined over a small field of characteristic 2. in this paper, we propose an algorithm to speed up scalar multiplication on an elliptic curve defined over a small field. The proposed algorithm uses the same field. The proposed algorithm uses the same technique as Muller's to get an expansion by the Frobenius map, but its expansion length is half of Muller's due to the reduction step (Algorithm 1). Also, it uses a more efficient algorithm (Algorithm 3) to perform multiplication using the Frobenius expansion. Consequently, the proposed algorithm is two times faster than Muller's. Moreover, it can be applied to an elliptic curve defined over a finite field with odd characteristic and does not require any precomputation or additional memory.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.54-59
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• 2011

Reliable starting capability of a gas turbine engine calls the engine industry's attention recently. So far the gas turbine engine performance researches have focused on the range between idle to Max rpm, but recent attention on the starting has brought interests in the range of "Sub-dile". As component characteristic maps are essential for the starting research, various kinds of studies have been doing and proposing ways to expand the existing maps toward sub-idle range. In this paper, previous studies were discussed and a new method suggested and validated.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1187-1196
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• 2019

Information security has become a major challenge with the advent of cloud and social networking sites. Conventional encryption algorithms might not be suitable for image encryption because of the large data size and high redundancy among the raw pixels of a digital image. In this paper, we generalize the encryption method for of color image proposed by Jeong et al. to color image encryption using parametric 3-dimensional chaotic cat map using Laplace expansion and C-MLCA. Through rigorous experiments, we demonstrate that the proposed new image encryption system provides high security and reliability.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.694-699
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• 2010

Reliable starting capability of a gas turbine engine calls the engine industry's attention recently. So far the gas turbine engine performance researches have focused on the range between idle to Max rpm, but recent attention on the starting has brought interests in the range of "Sub-dile". As component characteristic maps are essential for the starting research, various kinds of studies have been doing and proposing ways to expand the existing maps toward sub-idle range. In this paper, previous studies were discussed and a new method suggested and validated.

• Journal of applied mathematics & informatics
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• v.38 no.3_4
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• pp.249-254
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• 2020

Here, assume that X is a compact space. we show that if f is a locally nonexpansive map then f : X → X has the limit shadowing property if and only if f : CR(f) → CR(f) has the limit shadowing property. Also we prove that if f is a local expansion then f has the limit shadowing property.

• Journal of the Korean Mathematical Society
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• v.48 no.6
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• pp.1143-1152
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• 2011

The existence of periodic solutions for the planar Hamiltonian systems with positively homogeneous Hamiltonian is discussed. The asymptotic expansion of the Poincar$\acute{e}$ map is calculated up to higher order and some sufficient conditions for the existence of periodic solutions are given in the case when the first order term of the Poincar$\acute{e}$ map is identically zero.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.2
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• pp.245-250
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• 2009

We consider a code function from the unit interval which has a generalized dyadic expansion into a coding space which has an associated ultra metric. The code function is not a bi-Lipschitz map but a dimension-preserving map in the sense that the Hausdorff and packing dimensions of any subset in the unit interval and its image under the code function coincide respectively.

• Journal of the Korean Mathematical Society
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• v.45 no.1
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• pp.97-119
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• 2008

Electrical impedance tomography (EIT) problem with anisotropic anomalous region is formulated in a few different ways using boundary integral operators. The Frechet derivative of Neumann-to-Dirichlet map is computed also by using boundary integral operators and the boundary of the anomalous region is approximated by trigonometric expansion with Lagrangian basis. The numerical reconstruction is done in case that the conductivity of the anomalous region is isotropic.