• Journal of Digital Convergence
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• v.16 no.12
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• pp.593-602
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• 2018

The purpose of this study was to investigate the coloring properties of non-mordant dyes by examining local literature on silk fabric dyeing using red-colored natural dyes. Natural dyes can be prepared from the following 8 materials: purple-fleshed sweet potato, Impatiens balsamina, mulberry, fruits of Ligustrum japonicum Thunb, guava leaves, dansam, hibiscus flowers, and pruned branches of Prunus persica. To examine the surface color calculated $L^*$, $a^*$, $b^*$, ${\Delta}E^*$, and K/S value and H V/C. The variables considered in the dyeing experiment were dye concentration, dyeing temperature, dyeing time, and number of dyeing iterations, which were varied to evaluate the dyeing properties and color characteristics. As a result, the abovementioned variables, dye affinity, and red color expression were directly proportional to one another. In this study, it was found that red coloring can be obtained with natural dyes; moreover, excellent dyeing was achieved without the need for repeated dyeing or mordanting processes, which cause environmental pollution.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.133-141
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• 2005

We need to study on simulation method of user's mobility Patterns for the performance analysis of the location management in wireless mobile networks. For this purpose ,this paper presents a user mobility model of wireless mobile networks with regular Patterns Sometimes mobile users randomly move , but they show the movement characteristics that regularly change their locations in some patterns in given time slots. So, we suggest the mobility model that can describe user's time related movement patterns. This model consists of some elements-positions, transitions , transition Probabilities which are variable, and some geographical paths for each transitions. We describe the simulation method for users' mobilities with random movements and regular movements , too. The simulation results by the model show that the suggested model can generate movement scenarios having regular patterns related with location and time.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.322-331
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• 2009

This paper proposes an efficient data representation of stereo images using edge-based mesh optimization. Mash-based two dimensional warping for stereo images mainly depends on the performance of a node selection and a disparity estimation of selected nodes. Therefore, the proposed method first of all constructs the feature map which consists of both strong edges and boundary lines of objects for node selection and then generates a grid-based mesh structure using initial nodes. The displacement of each nodal position is iteratively estimated by minimizing the predicted errors between target image and predicted image after two dimensional warping for local area. Generally, iterative two dimensional warping for optimized nodal position required a high time complexity. To overcome this problem, we assume that input stereo images are only horizontal disparity and that optimal nodal position is located on the edge include object boundary lines. Therefore, proposed iterative warping method performs searching process to find optimal nodal position only on edge lines along the horizontal lines. In the experiments, we compare our proposed method with the other mesh-based methods with respect to the quality by using Peak Signal to Noise Ratio (PSNR) according to the number of nodes. Furthermore, computational complexity for an optimal mesh generation is also estimated. Therefore, we have the results that our proposed method provides an efficient stereo image representation not only fast optimal mesh generation but also decreasing of quality deterioration in spite of a small number of nodes through our experiments.

• Resources Recycling
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• v.32 no.3
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• pp.38-44
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• 2023

Leaching tests were conducted using sulfuric acid and sodium hydroxide solutions to remove impurities from domestic graphite concentrate. As a result of the leaching experiment using sulfuric acid solution and sodium hydroxide solution, respectively, the difference of removal efficiency was insignificant when the concentration of sodium hydroxide or sulfuric acid was 2 mol/L or more. The fixed carbon content increased with increasing the temperature in the sulfuric acid solution leaching, while it remains constant above 150℃ in sodium hydroxide solution. For the repeated sequential leaching tests, the leaching conditions were 2 mol/L NaOH, 200℃, 1 hour in the sodium hydroxide solution leaching and 2 mol/L H₂SO₄, 100℃, 1 hour in the sulfuric acid solution leaching, respectively. When sulfuric acid leaching followed by sodium hydroxide solution leaching was repeated 5 times, the fixed carbon increased to 99.95% and ash content decreased to 0.048%, while the fixed carbon increased to 99.98% and ash content was reduced to 0.018 when sodium hydroxide solution leaching followed by sulfuric acid solution leaching was repeated 5 times.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.4
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• pp.11-18
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• 2021

We propose a method that combines learning in a virtual environment and a real environment for indoor autonomous driving through reinforcement learning. In case of learning only in the real environment, it takes about 80 hours, but in case of learning in both the real and virtual environments, it takes 40 hours. There is an advantage in that it is possible to obtain optimized parameters through various experiments through fast learning while learning in a virtual environment and a real environment in parallel. After configuring a virtual environment using indoor hallway images, prior learning was carried out on the desktop, and learning in the real environment was conducted by connecting various sensors based on Jetson Xavier. In addition, in order to solve the accuracy problem according to the repeated texture of the indoor corridor environment, it was possible to determine the corridor wall object and increase the accuracy by learning the feature point detection that emphasizes the lower line of the corridor wall. As the learning progresses, the experimental vehicle drives based on the center of the corridor in an indoor corridor environment and moves through an average of 70 steering commands.

• Journal of the HCI Society of Korea
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• v.1 no.2
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• pp.19-26
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• 2006

This paper presents a novel pneumatic tactile display that can deliver some useful information. The air-jet display forms 5 by 5 arrays and features air nozzles with an external diameter of 2.4mm and internal diameter of 1.5 mm. In comparison with other tactile displays such as vibrotactile, there is little concrete psychophysical data relating to pneumatic displays, a fact which hinders their adoption. This paper addresses this challenge, and presents brief psychophysical studies examining localization rate, the two point threshold, stimulus intensity and the temporal threshold of cues produced by pneumatic air jets. Two groups of subjects were used in these studies, subsequently termed groups A and B. Both were comprised of eight participants. In the case of localization study we obtained 58.13% and 85.9% of localization rates each for dense display and sparse display. Two-points threshold test showed the length of gap between two air-jet stimuli which subjects can detect. However, it was formidable to find out precise temporal resolution of PTI owing to the limitation of capability of the pneumatic valves. Lastly, the results of stimulus intensity study suggest that by varying the size of a pneumatically created tactile stimulus, we can effectively vary its perceived magnitude.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.83-90
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• 2017

Electrical impedance tomography is a relatively new nondestructive imaging modality in which the internal conductivity distribution is reconstructed based on the injected currents and measured voltages through electrodes placed on the surface of a domain. In this paper, a fast iterative Gauss-Newton method is proposed to increase the spatial resolution as well as reduce the inverse computational time in the inverse problem, which could be applied to online binary mixture flow applications. To evaluate the reconstruction performance of the proposed method, numerical experiments have been carried out and the results are analyzed.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.75-82
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• 2012

In this paper, an improved community detection algorithm based on the modularity is proposed. The existing algorithm does not consider the information that the nodes have in checking the possible modularity increase, hence the computation may be inefficient. The proposed algorithm computes the node degree (weight) and sorts them in non-increasing order. By checking the possible modularity value increase for the nodes in the nonincreasing order of node weights, the algorithm finds the final solution more quickly than the existing algorithm does. Through the computational experiments, it is shown that the proposed algorithm finds a modularity as good as the existing algorithm obtains.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.110-112
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• 2011

GPU의 병렬성과 연산능력을 일반적인 공학적 문제 해결에 적용하는 GPGPU 컴퓨팅에 대한 연구가 최근 활발히 진행되고 있다. 비디오 압축과정에는 많은 양의 화소 데이터에 동일하게 반복되는 연산을 수행하는 알고리즘이 많이 적용되므로 GPGPU를 통한 고속 병렬 계산의 응용 분야로 매우 적합하다. H.264/AVC는 비디오를 압축하는 가장 최신의 국제표준으로 여러 제품군과 서비스에 대한 적용되어 시장에서 널리 사용되고 있다. 본 논문에서는 GPGPU의 응용 분야로 주목 받고 있는 비디오 압축 분야에 대한 적용으로 H.264/AVC의 화면내 예측 모드 결정과정에 GPGPU 병렬 프로그래밍을 적용하여 예측 모드 결정 속도를 향상하는 방법을 제안한다. GPU상에서의 데이터 병렬처리를 위해 CUDA C언어를 사용하였으며, CPU상에서의 연산은 C언어를 사용하여 구현되었다. GPU상에서 프레임 전체에 대한 화면내 예측 모드를 병렬적으로 결정함으로써 이에 소요되는 시간을 줄여 줄 수 있었다. 실험결과 GPU상에서 병렬적으로 예측 모드를 결정할 때 Full-HD급 영상에서 약 2.8배 정도의 속도 향상을 확인할 수 있었다. 향후 GPGPU 병렬 프로그래밍을 화면 내 예측뿐만 아니라 반복되는 연산을 수행하는 다른 알고리즘에도 적용하여 부호화기의 계산 부담을 덜어준다면 고속 실시간 비디오 압축 부호기 개발이 더욱 용이해 질것으로 기대된다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.49-56
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• 2006

최근 제조업을 보완하는 새로운 성장동력으로 서비스산업의 중요성이 부각되고 있다. 특히 무선 인터넷과 통신 기술의 발전은 신 서비스 창출의 기회를 마련해주는 동시에 서비스 시스템을 복잡하게 변화시키고 있다. 그러나 기존의 서비스 개발은 정성적인 판단과 직관에 의지하고 있으며, 서비스 개발 방법론은 개념적이고 추상적인 수준에서 제공되고 있다는 한계를 가진다. 이는 모바일 비즈니스(mobile business)와 같은 복잡한 서비스 시스템의 변화에 능동적으로 대처하지 못하고 있어, 모바일 비즈니스를 위한 실질적이고 체계적인 신 서비스 개발의 방법론의 필요성을 증가시킨다. 본 연구에서는 morphology 분석을 통해 모바일 비즈니스를 위한 체계적인 신서비스 개발 방법론을 제안한다. 특히 새로운 무선 통신 환경아래에서 급격한 변화를 맞고 있는 음악 산업을 대상으로 제안된 방법론의 활용 사례를 제시할 것이다. 제안된 방법론은 크게 4 단계로 구성된다. 첫째, 제공되는 서비스 시스템을 체계화하기 위해 morphology의 dimension들을 정의한다. 각 차원은 서비스 시스템의 하위 시스템이며, 이는 기존의 문헌조사와 연구를 통해 정의된다. 둘째, 각 차원별로 morphology의 shape를 정의한다. 셋째, 각 차원의 shape를 조합하여 과거의 서비스 시스템을 표현하고, morphology의 dimension과 shape를 확장한다. 넷째, morphology의 확장된 dimension과 shape를 조합하여 새로운 서비스를 구성한다. 제안된 접근법은 크게 두 가지 측면에서 강점을 가진다. 첫째, 신 서비스 아이디어의 획득을 용이하게 할 수 있다. morphology분석은 체계적인 설계 방법론을 창의적인 생각을 돕는 도구로 의미가 있다. 둘째, 체계적인 신 서비스의 개발을 가능하게 한다. morphology접근법은 M-비즈니스와 같은 복잡한 서비스 시스템을 구조적으로 분석하고, 개발할 수 있는 기틀이 된다.킹 대상을 도출할 때까지 추가적인 분석과정을 반복한다. 제안한 방법을 통하여 조직은 기술적 생산 가능성 외에도 다양한 조직 운영 관점에서 적절한 벤치마킹 대상을 선정할 수 있으며, 이에 따른 목표를 수립할 수 있을 것으로 기대한다. 또한 더 나아가 global efficiency 관점에서 효율적 조직이 되기 위하여 단계적인 벤치마킹 대상 선정과 이에 따른 목표를 수립하는데도 유용하리라 판단된다.$1.20{\pm}0.37L$, 72시간에 $1.33{\pm}0.33L$로 유의한 차이를 보였으므로(F=6.153, P=0.004), 술 후 폐환기능 회복에 효과가 있다. 4) 실험군과 대조군의 수술 후 노력성 폐활량은 수술 후 72시간에서 실험군이 $1.90{\pm}0.61L$, 대조군이 $1.51{\pm}0.38L$로 유의한 차이를 보였다(t=2.620, P=0.013). 5) 실험군과 대조군의 수술 후 일초 노력성 호기량은 수술 후 24시간에서 $1.33{\pm}0.56L,\;1.00{\ge}0.28L$로 유의한 차이를 보였고(t=2.530, P=0.017), 술 후 72시간에서 $1.72{\pm}0.65L,\;1.33{\pm}0.3L$로 유의한 차이를 보였다(t=2.540, P=0.016). 6) 대상자의 술 후 폐환기능에 영향을 미치는 요인은 성별로 나타났다. 이에 따른 폐환기능의 차이를 보면, 실험군의 술 후 노력성 폐활량이 48시간에 남자($1.78{\pm}0.61L$)가 여자($1.27{\pm}0.45L$)보다 더 높게 나타났으며 (t=2.170, P=0.042), 72시간에도 역시 남자($2.16{\pm}0.56L$)가 여자($1.50{\pm}0.47L$)보다 더 높았다(t=2.910, P=0.008). 술 후 일초 노