• 한국인터넷방송통신학회논문지
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• 제15권1호
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• pp.269-276
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• 2015

본 논문은 지금까지 미해결 문제로 알려진 정점 색칠 문제에 대한 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하였다. Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다". 즉, x(G)=k이다". Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하기 위해 본 논문은 교차되는 정점수와 한 정점에서 교차되는 클릭수를 구하여 모두 짝수이면 그래프의 최소 차수 ${\delta}(G)$ 정점을 최대독립집합 (minimum Independent set, MIS)에 포함시키는 방법을 적용하고, 둘 중 어느 하나가 홀수이면 최대 차수 ${\Delta}(G)$ 정점을 MIS에 포함시키는 방법을 적용하였다. 알고리즘 수행결과 얻은 MIS 개수가 x(G)=k이다. $3{\leq}k{\leq}8$인 $K_k$-클릭 합 교차 그래프에 대해 실험한 결과 모든 그래프에서 x(G)=k를 얻는데 성공하였다. 결국, "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다".는 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 성립함을 증명하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.775-792
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• 2015

Person re-identification is an important and challenging task in computer vision with numerous real world applications. Despite significant progress has been made in the past few years, person re-identification remains an unsolved problem. This paper presents a novel appearance-based approach to person re-identification. The approach exploits region covariance matrix and color histograms to capture the statistical properties and chromatic information of each object. Robustness against low resolution, viewpoint changes and pose variations is achieved by a novel signature, that is, the combination of Log Covariance Matrix feature and HSV histogram (LCMH). In order to further improve re-identification performance, third-party image sets are utilized as a common reference to sufficiently represent any image set with the same type. Distinctive and reliable features for a given image set are extracted through decision boundary between the specific set and a third-party image set supervised by max-margin criteria. This method enables the usage of an existing dataset to represent new image data without time-consuming data collection and annotation. Comparisons with state-of-the-art methods carried out on benchmark datasets demonstrate promising performance of our method.

• 대한수학회지
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• 제54권3호
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• pp.847-865
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• 2017

For a finite or an infinite set X, let $2^X$ be the power set of X. A class of simple graph, called strong Boolean graph, is defined on the vertex set $2^X{\setminus}\{X,{\emptyset}\}$, with M adjacent to N if $M{\cap}N={\emptyset}$. In this paper, we characterize the annihilating-ideal graphs $\mathbb{AG}(R)$ that are blow-ups of strong Boolean graphs, complemented graphs and preatomic graphs respectively. In particular, for a commutative ring R such that AG(R) has a maximum clique S with $3{\leq}{\mid}V(S){\mid}{\leq}{\infty}$, we prove that $\mathbb{AG}(R)$ is a blow-up of a strong Boolean graph if and only if it is a complemented graph, if and only if R is a reduced ring. If assume further that R is decomposable, then we prove that $\mathbb{AG}(R)$ is a blow-up of a strong Boolean graph if and only if it is a blow-up of a pre-atomic graph. We also study the clique number and chromatic number of the graph $\mathbb{AG}(R)$.

• 한국인터넷방송통신학회논문지
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• 제14권5호
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• pp.263-269
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• 2014

본 논문은 지금까지 미해결 문제로 알려진 정점 색칠 문제에 대한 Hadwiger 추측의 반증을 제시하였다. Hadwiger 추측은 "모든 $K_k$-minor free 그래프는 k-1개의 색으로 칠할 수 있다. 즉, $K_k$-마이너를 얻으면 ${\chi}(G)=k$이다." Hadwiger 추측을 적용하여 정점 색칠을 할 경우, 먼저 NP-완전 (NP-complete)인 $K_k$-마이너를 구하여 ${\chi}(G)=k$를 결정하고, 다시 NP-완전인 정점 색칠 문제를 풀어야 한다. Hadwiger 추측을 반증하기 위해 본 논문은 정점 색칠의 정확한 해를 O(V)의 선형시간으로 구하는 알고리즘을 제시하였다. 제안된 알고리즘은 그래프의 최소 차수를 가진 정점을 최대독립집합 (MIS)으로 하고, MIS 정점의 인접 정점 간선을 삭제한 축소된 그래프에 대해 이 과정을 반복하면서 하나의 색을 가진 MIS를 얻는다. 다음으로 MIS 정점의 간선을 삭제한 축소된 그래프에 대해 동일한 과정을 수행하여 MIS의 개수가 정점 채색수 ${\chi}(G)=k$가 되는 해를 얻는다. 제안된 알고리즘을 적용하여 NP-완전 문제인 완전 색칠 (total coloring) 채색수 ${\chi}^{{\prime}{\prime}}(G)$의 해를 구하는 알고리즘을 제안하였다. 제안된 알고리즘을 $K_4$-마이너 그래프에 적용한 결과 ${\chi}(G)=4$가 아닌 ${\chi}(G)=3$을 얻었다. 결국, Hadwiger 추측은 모든 그래프에 대해 적용되지 않음을 알 수 있다. 제안된 알고리즘은 마이너를 구하지 않으며, 주어진 그래프에 대해 직접 ${\chi}(G)=k$인 독립집합 마이너를 구하여 각 독립집합 정점들에 동일한 색을 배정하는 단순한 방법이다.

• 한국기계가공학회지
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• 제19권6호
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.357-360
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• 2007

Efficient extraction and update of imagery is a crucial element in establishing latest geospatial information in today's fast changing Information society. Provision of Quick Bird imagery, with 61cm resolution panchromatic imagery and 2.5m resolution multi-chromatic imagery is contributing greatly in the application field if high density geospatial information. This research have conducted digital plotting utilizing stereo images provided by QuickBird satellite and evaluated the accuracy through comparison and analysis with digital map results. It turned out that result has smaller error than standard deviation of scale of 1:5,000 set by the NGII. This proves that the production of digital map at scale of 1:5,000 is possible.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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• pp.7-10
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• 2000

There are many Problems such as low detection ratio, velocity and increase of false hit ratio on the detection of gradual scene changes with the previous shot transition detection algorithms. In this paper, we Propose an improved dissolve detection method using color information on low-frequency subband and edge elements on high-frequency subband. The Possible dissolve transition are found by analyzing the edge change ratio in the high-frequency subband with edge elements of each direction. Using the double chromatic difference on the lowest frequency subband, we have the improvement of the dissolve detection ratio. The simulation results show that the performance of the proposed algorithm is better than the conventional one for dissolve detection on a diverse set of uncompressed video sequences.

• 한국멀티미디어학회논문지
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• 제20권9호
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• pp.1502-1508
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• 2017

A musical key is a fundamental concept in Western music theory. It is a collective characterization of pitches and chords that together create a musical perception of the entire piece. It is based on a group of pitches in a scale with which a music is constructed. Each key specifies the set of seven primary chromatic notes that are used out of the twelve possible notes. This paper presents a method that identifies the key of a song using Hidden Markov Models given a sequence of chroma features. Given an input song, a sequence of chroma features are computed. It is then classified into one of the 24 keys using a discrete Hidden Markov Models. The proposed method can help musicians and disc-jockeys in mixing a segment of tracks to create a medley. When tested on 120 songs, the success rate of the music key identification reached around 87.5%.

• 한국컴퓨터정보학회논문지
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• 제16권6호
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• pp.179-186
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• 2011

본 논문은 화랑 문제의 최소 정점 경비원 수를 구하는 알고리즘을 제안하였다. n개의 사각형 방으로 구성된 화랑의 최소 경비원수는 정확한 해를 구하는 공식이 제안되었다. 그러나 단순하거나 장애물이 있는 다각형 또는 직각 다각형에 대해 최대 경비원수를 구하는 공식만이 제안되었으며, 최소 경비원수를 구하는 근사 알고리즘만이 제안되고 있다. n개의 정점으로 구성된 다각형 P에 대한 최대 정점 경비원 수를 구하는 방법은 Fisk가 다음과 같이 제안하였다. 첫 번째로, n-2개의 삼각형으로 구성된 삼각분할을 수행한다. 두 번째로 3색-정점색칠을 한다. 세 번째로 최소 원소를 가진 채색수를 정점 경비원의 위치로 결정한다. 본 논문에서는 지배집합으로 최소 정점 경비원 수를 구한다. 첫 번째로, 가능한 모든 가시적인 정점들 간에 간선을 그린 가시성 그래프를 얻는다. 두 번째로, 가시성그래프로부터 직접 지배집합을 얻는 방법과 가시성 행렬로부터 지배집합을 얻는 방법을 적용하였다. 다양한 화랑 문제에 적용한 결과 제안된 알고리즘은 단순하면서도 최소 정점 경비원 수를 얻을 수 있었다.

• 한국기계가공학회지
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• 제15권4호
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• pp.46-50
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• 2016

A laser head was designed for micro-scale patterning and joining applications. The target feature size of the pattern was $100{\mu}m$, and optics were designed to perform the target. Two singlet lenses were combined to minimize the chromatic aberration, and the geometry of the lenses was calculated by using the raytracing method with a commercial software program. As a restriction of lens design, the focal length was set at 100mm, and the maximum diameter of the lens or beam size was limited to 10mm for the assembly in the limited cage size. The maximum temperatures were calculated to be $1367^{\circ}C$, $1508^{\circ}C$, and $1905^{\circ}C$ for 10, 12, and 15 Watts of power, respectively. A specially designed laser head was used to compensate for the distance between the object and the lens. The detailed design mechanism and 3D data were presented. The optics design and detailed performance of the lens were analyzed by using MTF and spot diagram calculation.