• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.134-134
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• 2015

최근 액체 플라즈마에 대한 주된 이슈는 방전에 의해 발생하는 히드록실라디칼(OH-)과 버블이다. 액체 플라즈마를 이용한 다양한 응용분야에서는 히드록실라디칼에 주목하고 있다. 액체 플라즈마는 그래핀 파생물의 용액 친화도 향상을 위해 이용될 수 있다. 흑연이 포함된 과산화수소(H2O2) 용액에서 전기적인 방전으로 만들어진 히드록실라디칼로 그래핀 파생물의 용액 친화도를 향상시킨다. 이는 잠재적인 프린팅(printing) 기술 발전에 기대된다. 그리고 이 라디칼은 폐수에서 발암성의 트라이클로로아세트산(CCl3COOH)을 탈 염소하고 분해하는 역할을 하여 액체 플라즈마가 새로운 수처리 기술로 부상되고 있다. 또한 인체에서는 살균 작용을 하는 것 뿐만 아니라 단백질 고리를 끊는 역할을 하여 전립선 수술과 같은 인체수술에 적용될 수 있다. 최근 액체 플라즈마를 이용한 돼지 각막 임상수술에서 레이저와 필적할 정도로 매우 정밀하게 수술된 연구결과가 발표되어 인체 각막수술 적용에 기대된다. 이처럼 액체 플라즈마를 이용한 대부분의 응용분야에서 히드록실라디칼의 역할이 중요하다. 액체 플라즈마의 또 다른 이슈인 버블은 2가지의 역할을 한다. 첫 번째로 방전소스의 역할이다. 액체 속에 담긴 얇은 전극에 전압을 인가하면 전극 주변에서 강한 전기장의 발생으로 줄열(joule heating)에 의해 버블이 생성된다. 전극에서 버블이 생성되었을 때, 서로 다른 유전율을 가진 두 물질로 나누어진다. (버블 안은 공기로 상대 유전율 ${\varepsilon}r{\fallingdotseq}=1$, 용액은 ${\varepsilon}r{\fallingdotseq}=80$이다.) 시스템에 인가된 전압이 항복 전압(breakdown voltage)을 넘어서면 유전율이 상대적으로 낮은 버블내부에 강한 전기장이 걸리게 되어 방전이 일어난다. 만약 버블이 존재하지 않는다면 방전을 위해서 매우 높은 전압이 필요하다. 따라서 버블은 플라즈마 방전의 소스역할을 한다. 두번째로 버블은 전극의 부식을 방지하는 역할을 한다. 전극 부식은 주로 전기분해로 인한 산화반응에 의해 발생하는데 버블을 전극에 오래 머무르게 하면 부식을 방지할 수 있다. 이처럼 액체 플라즈마 시스템에서 버블의 역할들은 상당히 중요하다. 일반적으로 버블은 시스템에 인가하는 전원, 전극 극성 그리고 전압크기에 따라 거동이 달라진다. 시스템에 AC파워를 인가하면 버블은 주파수가 높을수록 전극에서 떨어지는 속도가 빨라지는 특성을 보인다. 핀 전극 극성이 음극일 때는 양극일 때보다 버블이 더 잘 생성된다. 또한 인가전압크기에 따라 거동이 달라지며 시스템에 같은 전압을 인가하여도 크기가 항상 같지 않고, 거동도 일관성을 보이지 않은 랜덤적인 모습을 보인다. 본 연구에서는 이 랜덤적인 버블의 거동을 정리하고 응용분야에서 중요하게 여기는 히드록실라디칼 생성에 대해 공부하기 위해 염류 용액(saline solution)에 핀(pin)-면(plane) 전극 구조를 설치하여 10Hz 주파수(1% duty cycle)를 가진 0-600V 구형펄스로 실험하였다. 실험을 통한 결과로서 랜덤적인 버블의 거동을 전극에서 버블이 떨어지는 속도와 플라즈마 특성에 따라 슈팅모드(shooting mode)와 유지모드(keeping mode) 2가지 모드로 분류하였다. 슈팅모드에서는 버블이 핀 전극에서 성장하지 못하고 빠른 속도로 떨어지는 모드로 플라즈마 방전이 잘 이루어지지 않는다. 반면 유지모드에서는 버블이 핀 전극에서 떨어지지 않고 지속적으로 성장한다. 이 모드에서는 펄스 시간 동안 하나의 버블로 연속적인 방전이 가능하다. 방전이 일어날 때 발생하는 히드록실라디칼의 생성은 버블 내부의 쉬스와 관련이 있다. 이 라디칼을 만들기 위해서는 높은 에너지가 요구되기 때문에 버블 내부의 쉬스(sheath)에서 만들어진다. 펄스 동안 쉬스는 주로 핀 전극 주변에서 유지되며 히드록실라디칼은 이곳에서 주로 만들어진다. 따라서 버블과 함께 쉬스도 성장하는 버블유지모드에서 슈팅모드보다 히드록실라디칼이 더 많이 생성된다.

• Information Systems Review
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• v.11 no.3
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• pp.125-146
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• 2009

The emergence of open source software(OSS) with its most prominent advantages creates a vast interest among practitioners. A study on Linux, the most well-known OSS, estimated that it would cost as 5.4 billion Euros taking over 73,000 person-years if it had been developed by conventional means. However, Linux has achieved only 0.65 percent of the operating system market for individual users while Microsoft windows family counts for nearly 90 percent of the market. Much of the effort being spent in the development of OSS is going to waste and potential value that OSS can bring to users is not being realized. Adoption of OSS is often accompanied by the discontinuance of existing software that is already in place. If users resist changing, they may not adopt OSS. Using the case of Linux, this study examines user resistance to change from the commercial operating software to the free operating system. This study identifies six sub-types of switching costs (uncertainty, emotional, setup, learning, lost benefit, and sunk costs) and tests their effects on user resistance to change based on a survey of 201 users. The results show that user resistance to change has a negative impact on the adoption of OSS. Further, this study shows that uncertainty and emotional costs have significant effects on user resistance to change. Beyond previous research on technology adoption, this research contributes towards an understanding of the switching costs leading to user resistance to change and offers suggestions to OSS practitioners for developing strategies to improve the adoption of OSS.

• Archives of design research
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• v.20 no.3 s.71
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• pp.129-140
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• 2007

This study attempts to investigate the personalized schemes of interface for the interactive TV sonics enhancing the satisfaction of users from the standpoints of the user and to suggest designing guidelines. In the preface, firstly, the purpose as well as structure of the study were described, the characteristics of the interactive TV and the personalization were defined. Also, it was attempted to understand the development directions of the basic media for services. In addition, the data and elements that became the ground for this study were arranged, including the elements for designing interface, the appraisal method of usability to evaluate the requirements of users, etc. Then, the interfaces of "SkyTouch", an interactive TV sonics by Skylife having the number of users reaching one million at the moment, that is the representative runner in the interactive TV, were analyzed. Then the needs central to the navigation structure and layout for the convenience of users through the evaluation of usability were examined and arranged. In addition, the designing directions of personalized interfaces were studied in the interactive TV by analyzing the web portal sites which were being carried out prior to the personalized services. Based on the data investigated and analyzed previously, the guidelines for the interface design for the personalization of the interactive TV were suggested by classifying the navigation structure and layout, and the personalized interface design was proposed according to the suggested guidelines by applying them directly to "SkyTouch" that is currently carrying out the interactive sonics although it provides limited services in an independent style.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.724-729
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• 2008

This paper presents the calculation of the required bandwidth of common frequency bandwidth applying queueing theory for maximizing the efficiency of frequency resource of WPAN(Wireless Personal Area Network) based Digital acoustic and communication devices. It assumed that LBT device(ZigBee) and FH devices (DCP, RFID and Bluetooth) coexist in the common frequency band for WPAN based Digital acoustic and communication devices. Frequency hopping (FH) and listen before talk (LBT) have been used for interference avoidance in the short range device (SRD). The LBT system transmits data after searching for usable frequency bandwidth in the radio wave environment. However, the FH system transmits data without searching for usable frequency bandwidth. The queuing theory is employed to model the FH and LBT system, respectively. As a result, the throughput for each channel was analyzed by processing the usage frequency and the interval of service time for each channel statistically. When common frequency bandwidth is shared with SRD using 250mW, it was known that about 35 channels were required at the condition of throughput 84%, which was determined with the input condition of Gaussian distribution implying safety communication. Therefore, the common frequency bandwidth is estimated with multiplying the number of channel by the bandwidth per channel. These methodology will be useful for the efficient usage of frequency bandwidth.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.859-864
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• 2017

IoT is a new emerging technology to lead the $4^{th}$ industry renovation and has been widely used in industry and home to increase the quality of human being. In this paper, IoT based face detection and recognition system for a smart elevator is developed. Haar cascade classifier is used in a face detection system and a proposed PCA algorithm written in Python in the face recognition system is implemented to reduce the execution time and calculates the eigenfaces. SVM or Euclidean metric is used to recognize the faces detected in the face detection system. The proposed system runs on RaspberryPi 3. 200 sample images in ORL face database are used for training and 200 samples for testing. The simulation results show that the recognition rate is over 93% for PP+EU and over 96% for PP+SVM. The execution times of the proposed PCA and the conventional PCA are 0.11sec and 1.1sec respectively, so the proposed PCA is much faster than the conventional one. The proposed system can be suitable for an elevator monitoring system, real time home security system, etc.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.51-62
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• 2019

In this study, a simple method to estimate the soil water content variation in a wide area was proposed using hyperspectral near-infrared images. The reflectance data of a sand, granite soils, and a kaolinite were measured by reflecting the soil samples with different wavelengths in the visible and near-infrared (VNIR) regions using hyperspectral cameras. The measured reflectances and parameters were used to build a water content prediction model using the Partial Least Square Regression (PLSR) analysis. In the water content prediction model, the Area of Reflectance (Near-infrared, NIR) parameter was the most suitable parameter to determine the water content. The parameter was applicable regardless of the soil type, as the coefficient of determination (R²) exceeded 0.9 for each soil sample. Additionally, the mean absolute percentage error (MAPE) was less than 15% when compared with the actual water content of the soil. Therefore, the predictability of water content variation for soils with water content lower than 50% was confirmed. Accordingly through this study, the predictability of water content variation in several soil types using the hyperspectral near-infrared images was confirmed. For further development, a model that incorporates soil classification would be required to improve the accuracy of the model and to predict higher range of water contents.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.337-343
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• 2013

The aims of this study were to compare genetic distances among 14 Phalaenopsis varieties using simple sequence repeat (SSR) and sequence-related amplified polymorphism (SRAP) marker systems and to determine the discrimination using SSR. A total of 111 SSR primers and 30 SRAP combinations were initially screened. Twelve SSR primers and thirty SRAP combinations showed high polymorphism among the 14 Phalaenopsis varieties including domestic breeding varieties, conserved in National Institute of Horticultural & Herbal Science (NIHHS). The amplified DNA fragments were separated by denaturing acrylamide gels and detected by silver staining method. A total of 474 polymorphic bands, including 55 by SSRs and 419 by SRAPs, were identified and used for genetic diversity analysis. Polymorphic bands were scored for calculating a simple matching coefficient of genetic similarity and cluster analysis with multi-variate statistical package (MVSP) 3.1. Fourteen Phalaenopsis varieties were classified into three major groups at similarity coefficient value of 0.683 and 0.66 using SRAP and SSR, respectively. Also we could discriminate these domestic breeding Palaenopsis varieties using only SSR 20 and SSR 22. The results indicate that SSR analysis is effective for discrimination among Phalaenopsis varieties and SRAP is useful for genetic diversity when there is no sequence information. These studied SSR and SRAP markers will be useful tools for genotype identification, germplasm conservation and genetic relationship study in Phalaenopsis.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.28-41
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• 2006

Due to the rapid development of multimedia appliances, the increasing amount of multimedia data enforces the development of automatic video analysis techniques. In this paper, a method of ToC generation is proposed for educational video contents. The proposed method consists of two parts: scene segmentation followed by scene annotation. First, video sequence is divided into scenes by the proposed scene segmentation algorithm utilizing the characteristics of educational video. Then each shot in the scene is annotated in terms of scene type, existence of enclosed caption and main speaker of the shot. The ToC generated by the proposed method represents the structure of a video by the hierarchy of scenes and shots and gives description of each scene and shot by extracted features. Hence the generated ToC can help users to perceive the content of a video at a glance and. to access a desired position of a video easily. Also, the generated ToC automatically by the system can be further edited manually for the refinement to effectively reduce the required time achieving more detailed description of the video content. The experimental result showed that the proposed method can generate ToC for educational video with high accuracy.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.41-49
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• 2003

This study was undertaken to observe the histopathologic changes in submandibular glands of the white rats when exposed to megavoltage fractionated dose of CLINAC 2100 C-D 6 MV X-RAY irradiation and 42 female white rats, weighing approximately 100gm, were divided into control and 2 experimental groups. At sacrifice, submandibular glands were excised and examined microscopically and electromicroscopically. The results were as follows : 1. The acinar cells of submandibular gland showed damage varied with dose, 12 Gy resulted in very mild injury while 24 Gy caused extensive injury. 2. The acinar cells of sumandibular gland showed similar ultrastructual alterations, appeared as pleomorphic nucleus, decreased numbers and pleomorpgism of secretory granules, distention of rough endoplasmic reticulum, expansion and pallor appearance of mitochondria, and hypertrophy of Golgi complex. 3. A serous cells were the most sensitive components, displaying morphological alterations of radiation damage as early as 3 hours, followed by submandibular seromucinous cells and secretory tubular cells. 4. The mucous cells, as well as the whole ductal lining cells, displayed no significant alterations. 5. No evidence of microvascular injury through whole experimental groups indicated that microvascular impairment dose not contribute to early. salivary gland injury.

• Journal of Information Management
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• v.41 no.2
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• pp.47-69
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• 2010

Open innovation is a phenomenon that has been widely accepted by both practice and theory over the last few years. On the contrary, partner relationships have attracted little attention while the open innovation could not be emerged without the link to partners. This paper identifies and evaluates a framework for the partner relationships and open innovation processes. Based on the literatures regarding open innovation and partner relationships, we propose the framework of matrix type. We present results based on 352 open innovation cases reported during 2002-2009, and each case is classified into 5 different categories of the framework. JV-C(Joint Venture relationship & Coupled process) archetype has dominated the cases with 178 cases(50.6%) where JV-O(Joint Venture relationship & Outside-In process) follows JV-C with 124 cases(35.2%). No significant change has been found in the number of cases after 2003 when open innovation firstly suggested. However, the number sharply increases in 2009 by boom in JV-C and JV-O. These results show the importance of partner relationships and preference toward Joint Venture relationship in open innovation, while the conventional approaches has just focused on value-chain partnership. We find remarkable collaboration cases contributed by universities and government invested research centers, so the role of non-profit R&D organizations has also been discussed.