• 충청수학회지
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• 제37권2호
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• pp.57-66
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• 2024

In this paper, we study how the Hilbert polynomial, associated with a reduced closed subscheme X of codimension 2 in ℙ^N, reveals geometric information about X. Although it is known that the Hilbert polynomial can tell us about the scheme's degree and arithmetic genus, we find additional geometric information it can provide for smooth varieties of codimension 2. To do this, we introduce the concept of Gotzmann coefficients, which helps to extract more information from the Hilbert polynomial. These coefficients are based on the binomial expansion of values of the Hilbert function. Our method involves combining techniques from initial ideals and partial elimination ideals in a novel way. We show how these coefficients can determine the degree of certain geometric features, such as the singular locus appearing in a generic projection, for smooth varieties of codimension 2.

• 한국전자통신학회논문지
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• 제8권8호
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• pp.1187-1193
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• 2013

본 논문은 사실적인 3D 얼굴 모델링과 얼굴 표정 생성 시스템을 제안한다. 사실적인 3D 얼굴 모델링 기법에서 개별적인 3D 얼굴 모양과 텍스쳐 맵을 만들기 위해 Generic Model Fitting 기법을 적용하였다. Generic Model Fitting에서 Deformation Function을 계산하기 위해 개별적인 얼굴과 Generic Model 사이의 대응점을 결정하였다. 그 후, Calibrated Stereo Camera로부터 캡쳐 된 영상들로부터 특징점을 3D로 복원하였다. 텍스쳐 매핑을 위해 Fitted된 Generic Model을 영상으로 Projection하였고 사전에 정의된 Triangle Mesh에서 텍스쳐를 Generic Model에 매핑 하였다. 잘못된 텍스쳐 매핑을 방지하기 위해, Modified Interpolation Function을 사용한 간단한 방법을 제안하였다. 3D 얼굴 표정을 생성하기 위해 Vector Muscle기반 알고리즘을 사용하고, 보다 사실적인 표정 생성을 위해 Deformation 과 vector muscle 기반의 턱 rotation을 적용하였다.

• Journal of Information Technology Applications and Management
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• 제12권1호
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• pp.35-48
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• 2005

An architectural framework is developed for integrating geospatial and temporal data with relational information from which a spatio-temporal data warehouse (STDW) system is built. In order to implement the STDW, a generic conceptual model was designed that accommodated six dimensions: spatial (map object), temporal (time), agent (contractor), management (e.g. planting) and tree species (specific species) that addressed the 'where', 'when', 'who', 'what', 'why' and 'how' (5W1H) of the STDW information, respectively. A formal algebraic notation was developed based on a triplet schema that corresponded with spatial, temporal, and relational data type objects. Spatial object structures and spatial operators (spatial selection, spatial projection, and spatial join) were defined and incorporated along with other database operators having interfaces via the generic model.

• 충청수학회지
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• 제34권2호
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• pp.181-188
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• 2021

Let X be a nondegenerate reduced closed subscheme in ℙⁿ. Assume that π_q : X → Y = π_q(X) ⊂ ℙ^n-1 is a generic projection from the center q ∈ Sec(X) \ X where Sec(X) = ℙⁿ. Let Z be the singular locus of the projection π_q(X) ⊂ ℙ^n-1. Suppose that I_X has the almost minimal presentation, which is of the form R(-3)^β_2,1 ⊕ R(-4) → R(-2)^β_1,1 → I_X → 0. In this paper, we prove the followings: (a) Z is either a linear space or a quadric hypersurface in a linear subspace; (b) $H^1({\mathcal{I}_X(k)})=H^1({\mathcal{I}_Y(k)})$ for all k ∈ ℤ; (c) reg(Y) ≤ max{reg(X), 4}; (d) Y is cut out by at most quartic hypersurfaces.

• IEIE Transactions on Smart Processing and Computing
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• 제4권6호
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• pp.384-390
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• 2015

There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.

• Animal Systematics, Evolution and Diversity
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• 제29권3호
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• pp.259-266
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• 2013

A newly recorded aorid species, Paragrandidierella minima Ariyama, 2002, from Korean waters is reported with a description and illustrations, and its generic features are considered. This species is characterized by the carpochelate gnathopod 1 in matured male, the posterodistal protrusion on peduncle 5 of antenna 2, the absence of the apical spine on inner plate of maxilliped, the minute apical projection on inner lobe of lower lip, the acute posteroproximal extension on the basis of each pereopod 5 and 6, the shape of uropods and telson, and the large inter-ramal process of uropod 1. This is the first report of the genus Paragrandidierella from Korea.

• 한국인지과학회:학술대회논문집
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• 한국인지과학회 2000년도 춘계 학술대회
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• pp.157-163
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• 2000

이 글은 최근 인지언어학에서 기본적인 핵심이론 중의 하나로 자리잡고 있는 '정신공간 이론'(mental space theory)에 대한 이론적인 소개와 함께 의미구성에 있어서 중요한 개념의 하나인 '사상'(mappings)의 문제를 다루고자 한다. 1994년 이후 Fauconnier와 Fauconnier & Turner 등을 중심으로 진행되어 오고 있는 정신공간 이론에서는, 언어의 의미를 궁극적으로 인지적 공간들 사이의 상호관계가 언어로 '투사'(projection)된 것으로 간주한다. 그리고 기존의 근원영역과 목표영역 사이의 직접적이고 체계적인 사상, 이른바 '두 영역 모델'의 대안으로 '다공간 모델'을 제시하고 있다. 다공간 모델 속에는 '포괄공간'(generic space)과 '혼합공간'(blending space)이 설정되는데, 그 중에서 포괄공간은 근원공간과 목표공간의 모든 개념이나 추상적인 도식 등이 반영되어 있는 반면, 혼합공간은 실제의 다양한 개념적 혼합의 결과로 나타나며, 입력된 공간에서 나타나는 상응되는 부분들 사이의 연결을 활용하고 발전시키기 때문에 그 자체가 또 다른 혼합공간의 입력공간에서 일어나는 개념적 사상의 양상은 매우 다양할 뿐만 아니라 의미구성에 있어서도 중요한 역할을 한다. 이 글에서는 합성어와 같은 어휘적 측면은 물론, 일상의 문장 표현을 통해 나타나는 개념적 사상의 다양한 양상을 고찰하고자 한다.

• Journal of information and communication convergence engineering
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• 제11권3호
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• pp.207-215
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• 2013

In this paper, we address the challenging computer vision problem of obtaining a reliable facial expression analysis from a naturally interacting person. We propose a system that combines a 3D generic face model, 3D head tracking, and 2D tracker to track facial landmarks and recognize expressions. First, we extract facial landmarks from a neutral frontal face, and then we deform a 3D generic face to fit the input face. Next, we use our real-time 3D head tracking module to track a person's head in 3D and predict facial landmark positions in 2D using the projection from the updated 3D face model. Finally, we use tracked 2D landmarks to update the 3D landmarks. This integrated tracking loop enables efficient tracking of the non-rigid parts of a face in the presence of large 3D head motion. We conducted experiments for facial expression recognition using both framebased and sequence-based approaches. Our method provides a 75.9% recognition rate in 8 subjects with 7 key expressions. Our approach provides a considerable step forward toward new applications including human-computer interactions, behavioral science, robotics, and game applications.

• 대한원격탐사학회지
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• 제15권3호
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• pp.167-175
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• 1999

원격탐사 관련 핵심기술은 최근에 국방, 의료영상, 환경, 지질 등과 같은 광범위한 분야에서 활용범위를 확대하고 있다. 1cm ~ 수십 cm 파장의 파를 관측하는 마이크로파 원격탐사 기술은 반사 적외선 원격탐사나 열 적외선 원격탐사 기술에 비해 날씨조건과 밤낮에 관계없이 탐사를 수행할 수 있다는 장점을 가지고 있다. 마이크로파 영상레이다인 합성 개구 레이다를 이용한 영상화 방식은 응용목적에 따라 stripmap 방식, spotlight 방식, 그리고 inverse 방식으로 구분된다. 본 논문에서는 inverse 방식으로 지상에 고정된 레이다가 비행하는 항공체를 영상화하는 기법에 대해서 기술하였다. 비행 항공체의 영상화 기법은 자동 펴적인식 시스템 구축시 중요한 기술단계이며, 최근 이 분야에 대해 활발히 연구되고 있다. 비행 항공체를 영상화하기 위해 제안된 3가지 방식인 퓨리에 처리 기법, 시간-n 주파수 처리 기법, 그리고 투시로부터 복원 기법을 소개한 후, 각 방식의 장단점을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.368-391
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• 2018

Face recognition (FR) with a single sample per person (SSPP) is common in real-world face recognition applications. In this scenario, it is hard to predict intra-class variations of query samples by gallery samples due to the lack of sufficient training samples. Inspired by the fact that similar faces have similar intra-class variations, we propose a virtual sample generating algorithm called k nearest neighbors based virtual sample generating (kNNVSG) to enrich intra-class variation information for training samples. Furthermore, in order to use the intra-class variation information of the virtual samples generated by kNNVSG algorithm, we propose image set based multimanifold discriminant learning (ISMMDL) algorithm. For ISMMDL algorithm, it learns a projection matrix for each manifold modeled by the local patches of the images of each class, which aims to minimize the margins of intra-manifold and maximize the margins of inter-manifold simultaneously in low-dimensional feature space. Finally, by comprehensively using kNNVSG and ISMMDL algorithms, we propose k nearest neighbor virtual image set based multimanifold discriminant learning (kNNMMDL) approach for single sample face recognition (SSFR) tasks. Experimental results on AR, Multi-PIE and LFW face datasets demonstrate that our approach has promising abilities for SSFR with expression, illumination and disguise variations.