• Genomics & Informatics
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• 제20권1호
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• pp.2.1-2.11
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• 2022

The method of single-cell RNA sequencing has been rapidly developed, and numerous experiments have been conducted over the past decade. Their results allow us to recognize various subpopulations and rare cell states in tissues, tumors, and immune systems that are previously unidentified, and guide us to understand fundamental biological processes that determine cell identity based on single-cell gene expression profiles. However, it is still challenging to understand the principle of comprehensive gene regulation that determines the cell fate only with transcriptome, a consequential output of the gene expression program. To elucidate the mechanisms related to the origin and maintenance of comprehensive single-cell transcriptome, we require a corresponding single-cell epigenome, which is a differentiated information of each cell with an identical genome. This review deals with the current development of single-cell epigenomic library construction methods, including multi-omics tools with crucial factors and additional requirements in the future focusing on DNA methylation, chromatin accessibility, and histone post-translational modifications. The study of cellular differentiation and the disease occurrence at a single-cell level has taken the first step with single-cell transcriptome and is now taking the next step with single-cell epigenome.

• 대한임베디드공학회논문지
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• 제14권6호
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• pp.295-311
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• 2019

The smart product market is growing year by year and is being used in many areas. There are various ways of interacting with smart products and users by inputting voice recognition, touch and finger movements. It is most important to detect an accurate hand region as a whole step to recognize hand movement. In this paper, we propose a method to detect accurate hand region in real time in various environments. A conventional method of detecting a hand region includes a method using depth information of a multi-sensor camera, a method of detecting a hand through machine learning, and a method of detecting a hand region using a color model. Among these methods, a method using a multi-sensor camera or a method using a machine learning requires a large amount of calculation and a high-performance PC is essential. Many computations are not suitable for embedded systems, and high-end PCs increase or decrease the price of smart products. The algorithm proposed in this paper detects the hand region using the color model, corrects the problems of the existing hand detection algorithm, and detects the accurate hand region based on various experimental environments.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.133-136
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• 1997

The human chromosome analysis is widely used to diagnose genetic disease and various congenital anomalies. Many researches on automated chromosome karyotype analysis has been carried out, some of which produced commercial systems. However, there still remains much room or improving the accuracy of chromosome classification. In this paper, We propose an optimal pattern classifier by neural network to improve the accuracy of chromosome classification. The proposed pattern classifier was built up of multi-step multi-layer neural network(MMANN). We reconstructed chromosome image to improve the chromosome classification accuracy and extracted three morphological features parameters such as centromeric index(C.I.), relative length ratio(R.L.), and relative area ratio(R.A.). This Parameters employed as input in neural network by preprocessing twenty human chromosome images. The experiment results show that the chromosome classification error is reduced much more than that of the other classification methods.

• Advances in aircraft and spacecraft science
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• 제1권4호
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• pp.427-441
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• 2014

Orbit-raising is an important step to place spacecraft from parking orbits into working orbits. Attitude control system design is crucial in the success of orbit-raising. Several text books have discussed this design and focused mainly on the traditional methods based on single-input single-output (SISO) transfer function models. These models are not good representations for many orbit-raising control systems which have multiple thrusters and each thruster has impact on the attitude defined by all outputs. Only one published article is known to use a more suitable multi-input multi-output (MIMO) Euler angle model in spacecraft orbit-raising attitude control system design. In this paper, a quaternion based MIMO model for the orbit-raising attitude control system design is proposed. The advantages of using quaternion based model for orbit-raising control system designs are (a) there is no need for mathematical transformations because the attitude measurements are normally given by quaternion, (b) quaternion based model does not depend on rotational sequences, which reduces the chance of human errors, and (c) the singular point of reduced quaternion model is the farthest from the operational point where linearization is performed. We will show that performance of quaternion model based design will be as good as the performance of Euler angle model based design for orbit-raising problem.

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1160-1166
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• 2006

혼잡한 현대의 교통 상황에서 교통질서를 유지하기 위해 차량에 대한 정보를 아는 것은 매우 중요한 일이다. 본 논문은 차량의 정보를 아는데 있어서 가장 중요한 차량 번호판을 인식하는 새로운 기법을 소개한다. 제안하는 기법은 물체를 분류하는데 있어서 다른 방법보다 우수하다고 알려진 SVM을 이용한다. 번호판 영역을 찾는데는 이중분류 SVM을 이용하고 번호판 문자 인식에서는 다중 분류 SVM을 이용한다. 여러 단계의 영상처리 과정과 인식 과정을 거쳐서 실시간에 처리할 수 있는 시스템으로 여러 종류의 차량 번호판에 대한 인식도 가능하게 한다. 제안한 기법을 이용한 실제적 환경에서의 영상과 인식에 대한 실험결과를 통하여 성능을 입증하였다.

• Earthquakes and Structures
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• 제4권1호
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• pp.109-132
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• 2013

Current codes incorporate simplified methods for the prediction of acceleration demands on secondary structural and non-structural elements at different levels of a building. While the use of simple analysis methods should be advocated, damage to both secondary structural and non-structural elements in recent earthquakes have highlighted the need for improved design procedures for such elements. In order to take a step towards the formation of accurate but simplified methods of predicting floor spectra, this work examines the floor spectra on elastic and inelastic single-degree of freedom systems subject to accelerograms of varying seismic intensity. After identifying the factors that appear to affect the shape and intensity of acceleration demands on secondary structural and non-structural elements, a new series of calibrated equations are proposed to predict floor spectra on single degree of freedom supporting structures. The approach uses concepts of dynamics and inelasticity to define the shape and intensity of the floor spectra at different levels of damping. The results of non-linear time-history analyses of a series of single-degree of freedom supporting structures indicate that the new methodology is very promising. Future research will aim to extend the methodology to multi-degree of freedom supporting structures and run additional verification studies.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.9-16
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• 2018

광원 자체의 밝기가 낮거나 그림자 등의 이유로 어두운 영역을 포함하는 이미지는 Retinex 기반의 영상화질 개선기법을 통해 주관적 화질을 높일 수 있다. Retinex 이론은 인간의 시각 시스템이 장면을 인식할 때 특정 위치에서의 장면의 밝기를 인식하는 것이 아니라 주변과의 상대적인 밝기를 인식하는 특징을 적용한 방법으로 크게 SSR, MSR, MSRCR의 방법으로 나눌 수 있다. 제안하는 방법은 컬러복원단계를 포함하고 있는 MSRCR에 기반한 방법으로 크게 3단계로 구성되어 있다. 첫 번째 단계에서는 기존의 MSRCR 방법을 적용하고 두 번째 단계에서 MSRCR 출력의 동적 영역을 이미지의 히스토그램분포에 따라 조정한다. 마지막 단계에서는 인간의 시각특성을 고려한 로그변환함수를 이용하여 Retinex 출력 값을 디스플레이 동적영역으로 변환한다. 실험결과 제안하는 알고리즘은 전체적으로 어두운 이미지뿐만 아니라 밝은 영역과 어두운 영역을 모두 포함하는 이미지에서도 주관적 화질을 효과적으로 증가시키는 것을 볼 수 있다. 특히 낮은 밝기를 갖는 이미지의 경우 제안한 알고리즘은 기존의 방법들 보다 높은 성능향상을 보였다.

• 한국지진공학회논문집
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• 제7권6호
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• pp.71-80
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• 2003

구조물의 내진 성능을 정확히 평가하기 위해서는 비선형 시각 이력 해석이 필요하지만 실용성과 단순성 측면에서 약산법이 대안이 될 수 있으며, 다층 구조물을 등가 단자유도계로 치환할 때 다층 구조물의 모드벡터는 구조물이 탄성 또는 탄소성 상태에 상관없이 탄성 상태에서의 모드 형상으로 가정되지만, 항복이 발생한 후 증가하는 하중단계에서 구조물은 비탄성으로 되기 때문에 변위 모드 특성들도 변화된다. 본 논문은 항복 이후의 구조물의 모드 변화를 고려한 비선형 변위모드를 이용하여 다자유도계를 등가 단자유도계로 변환하는 방법을 제시하였으며, 변환된 등가 단자유도계의 변위응답을 근거로 추정한 복합 구조물의 최상층 변위와 실제 지진교란을 받는 복합 구조물의 비선형 동적해석에 의한 최상층 변위를 비교함으로서 복합구조물의 지진응답예측을 위한 비선형 변위모드법의 적용성과 신뢰성을 검토하였다.

• Journal of Communications and Networks
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• 제15권1호
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• pp.77-86
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• 2013

Cognitive radio (CR) has emerged as one of effective methods to enhance the utilization of existing radio spectrum. Main principle of CR is that secondary users (SUs) are allowed to use the spectrum unused by primary users (PUs) without interfering PU's transmissions. In this paper, PUs operate on a slot-by-slot basis and SUs try to exploit the slots unused by PUs. We propose OSA protocols in the single channel and we propose an opportunistic spectrum access (OSA) protocols in the multi-channel cognitive radio networks with one control channel and several licensed channels where a slot is divided into contention phase and transmission phase. A slot is divided into reporting phase, contention phase and transmission phase. The reporting phase plays a role of finding idle channels unused by PUs and the contention phase plays a role of selecting a SU who will send packets in the data transmission phase. One SU is selected by carrier sense multiple access / collision avoidance (CSMA/CA) with request to send / clear to send (RTS/CTS) mechanism on control channel and the SU is allowed to occupy all remaining part of all idle channels during the current slot. For mathematical analysis, first we deal with the single-channel case and we model the proposed OSA media access control (MAC) protocol by three-dimensional discrete time Markov chain (DTMC) whose one-step transition probability matrix has a special structure so as to apply the censored Markov chain method to obtain the steady state distribution.We obtain the throughput and the distribution of access delay. Next we deal with the multi-channel case and obtain the throughput and the distribution of access delay by using results of single-channel case. In numerical results, our mathematical analysis is verified by simulations and we give numerical results on throughput and access delay of the proposed MAC protocol. Finally, we find the maximum allowable number of SUs satisfying the requirements on throughput and access delay.

• 품질경영학회지
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• 제47권1호
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• pp.163-186
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• 2019

Purpose: The purpose of this study was to present a methodology for assessing the efficiency of supply chain quality management considering characteristics of defense industries to provide academic and policy implications for strengthening quality competitiveness of military supplies. Methods: Using the defense industry's empirical data, conduct an efficiency evaluation by utilizing a multi-stage DEA/Entropy Model for defense industries subject to the quality level survey of military goods manufacturers in 2017. Results: The results of this study are as follows; the first step of the multi-stage DEA model, Quality Management Performance Efficiency Analysis, shows that the CCR model and the BCC model are more efficient than the parent company. the second stage of the multi-stage DEA model showed that the CCR model was slightly more efficient than the parent company and the BCC model was more efficient than the parent.the overall efficiency value of the multistage DEA model, calculated by multipointing the efficiency value of the first stage by the second stage, was more efficient than the parent. Conclusion: The results of this study show that the efficiency of supply chian quality management performance and profitability in the defense industry can be analyzed for the first time using the multistage DEA/Entropy model to identify specific inefficiencies and support objective decision making.