• Journal of Biosystems Engineering
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• 제36권5호
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• pp.326-333
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• 2011

The need for rapid on-site monitoring of hydroponic macronutrients has led to the use of ion-selective electrodes, because of their advantages over spectrophotometric methods, including simple methodology, direct measurement of analyte, sensitivity over a wide concentration range, and low cost. Stability and repeatability of response can be a concern when using multiple ion-selective electrodes to measure concentrations in a series of samples because accuracy might be limited by drifts in electrode potential. A computer-based measurement system could improve accuracy and precision because of both consistent control of sample preparation and easy calibration of sensors. Our goal was to investigate the applicability of a cobalt-based electrode used in conjunction with a laboratory-made automated test stand for quantitative determination of ${PO_4}^-$ in hydroponic solution. Six hydroponic solutions were prepared by diluting highly concentrated paprika hydroponicsolution to provide a concentration range of 1 to 300 ppm $PO_4$-P. A calibration curve relating electrode response to phosphate in paprika hydroponic solution titrated to pH 4 with 0.025M KHP was developed based on the Nikolskii-Eisenman equation with a coefficient of determination ($R^2$) of 0.94. The laboratory-made test stand consisting of three cobalt-based electrodes measured phosphate concentrations similar to those obtained with standard laboratory methods (a regression slope of 0.98 with $R^2$ = 0.80). However, the y intercept was relatively high, 30 ppm, probably due to the relatively large amount of variation present among multiple measurements of the same sample. Further studies on the high variation in EMFs obtained with cobalt electrodes during replicate measurements were required for P estimations comparable to those obtained with standard laboratory instruments.

• 디지털융복합연구
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• 제13권6호
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• pp.267-273
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• 2015

자칫 지루하게 느껴질 수 있는 책꽂이를 사용자의 행위에 의해 색상을 변화 시키며 즐길 수 있는 조명의 기능을 포함한 새로운 개념의 책꽂이로 디자인 하였다. 책꽂이의 조명을 탈착 가능하도록 디자인 하여 조명만을 따로 사용할 수도 있고, 조명 책꽂이는 모듈화 되어 있으며 메인 조명 책꽂이는 MCU(Micro Controller Unit), RGB LED와 컬러센서를 포함하고 있어 조명 책꽂이를 중심으로 아홉 개까지 네 방향으로 확장이 가능하다. 확장 가능한 다수의 조명 책꽂이는 MCU와 컬러센서를 내장하고 있지 않으며 단지 RGB LED만이 설치되어 있고 전원은 메인조명 책꽂이에서 공급 받을 수 있는 배선장치만을 가지고 있다. 메인 조명 책꽂이를 통해 전원과 색상 신호만을 전달 받아 서브 조명 책꽂이들은 조명의 색상을 변화 시킬 수 있다. 또한 사물인터넷의 기능을 포함한다. 본 연구는 이러한 센서를 이용해 책꽂이의 조명을 조절할 수 있는 모듈화된 디자인 제품의 제안이다.

• 한국정밀공학회지
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• 제25권8호
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• pp.45-50
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• 2008

An ink jetting measurement system has been developed such that the velocity as well as the volume of ink droplets can be measured. In order to measure the ink droplet, a strobe LED light was synchronized to the droplet firing signal in order to obtain frozen droplet images. Then, a LabVIEW based software was developed for the analysis of the droplet image. For the efficient droplet analysis, a user generated rectangular shaped ROI (Region of Interest) was used. By using ROI, the ink droplet image can be easily isolated from the other structures such as printhead and the processing area can be minimized.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.247-249
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• 2007

Crown parameters are important roles in tree species identification, because the canopy is the aggregate of all the crowns. However, crown measurements with spaceborne image data have remained more difficult than on aerial photographs since trees show more structural detail at higher resolutions. This recognized problem led to the initiation of the research to determine if high resolution satellite image data could be used to identify and classify single tree species. In this paper, shape parameters derived from pixel-based crown area measurements and texture features derived from GLCM parameters in QuickBird image were tested and compared for individual tree species identification. As expected, initial studies have shown that the crown parameters and the canopy texture parameters provided a differentiating method between coniferous trees and broad-leaved trees within the compartment(less than forest stand) for single extraction from spaceborne high resolution image.

• 한국전산구조공학회논문집
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• 제15권2호
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• pp.293-303
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• 2002

고장도 재료의 사용과 시공기술의 발달로 경기장 관람석이 장경간화 유연화 되어 구조물의 고유진동수가 매우 낮아지고 있다. 경기장 관람석구조물은 사람의 율동적인 움직임에 의하여 공진 또는 공진과 유사한 거동이 일어날 수 있으므로 진동에 대한 구조물의 안전성 및 사용성에 대한 검토가 요구된다. 경기장 관람석의 효과적인 설계를 위해서는 경기장 관람석에 가해지는 동적하중에 대한 분석과 경기장 관람석의 거동에 대한 정확한 분석이 있어야 한다. 경기장 관람석에 가해지는 동적하중은 매우 다양하며 수식적으로 표현하기가 쉽지 않기 때문에 계측한 동적하중을 적용하는 것이 바람직하다. 그리고 판요소로 이루어진 경기장관람석의 정확한 진동해석을 위해서는 구조물을 조밀하게 나누어야 하기 때문에 해석시간이 길어지게 된다. 또한 경기장 전체 구조물의 진동해석에 있어서 경기장 전체 구조물을 세분화하여 모델링하는 것은 매우 어려울 뿐만 아니라 절점 수가 매우 많아지므로 절점수가 제한되어 있는 상용프로그램으로는 해석이 불가능할 수도 있다. 본 연구에서는 경기장 관람객의 여러 가지 움직임에 의하여 야기되는 다양한 동적하중을 계측하여 분석하였다. 그리고 판요소로 이루어진 경기장 관람석의 동적특성을 비교적 잘 표현할 수 있으면서도 절점을 줄일 수 있는 효과적인 해석방법을 제안하였다. 제안된 방법의 정확성과 효율성을 살펴보기 위하여 경기장 관람석의 진동해석을 수행하였다.

• Journal of Korean Neurosurgical Society
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• 제59권4호
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• pp.385-391
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• 2016

Objective : The purpose of this study was to evaluate long-term follow-up radiologic/clinical outcomes of patients who underwent anterior cervical discectomy and inter-body fusion (ACDF) with stand-alone cages (SAC) in a single academic institution. Methods : Total 99 patients who underwent ACDF with SAC between February 2004 and December 2012 were evaluated retrospectively. A total of 131 segments were enrolled in this study. Basic demographic information, radiographic [segmental subsidence rate, fusion rate, C2-7 global angle, and segmental angle changes)/clinical outcomes (by Odom's criteria and visual analog score (VAS)] and complications were evaluated to determine the long-term outcomes. Results : The majority were males (55 vs. 44) with average age of 53.2. Mean follow-up period was 62.9 months. The segmental subsidence rate was 53.4% and fusion rate was 73.3%. In the subsidence group, anterior intervertebral height (AIH) had more tendency of subsiding than middle or posterior intervertebral height (p=0.01). The segmental angle led kyphotic change related to the subsidence of the AIH. Adjacent segmental disease was occurred in 18 (18.2%) patients. Total 6 (6%) reoperations were performed at the index level. There was no statistical significance between clinical and radiological outcomes. But, overall long-term clinical outcome by Odom's criteria was unsatisfactory (64.64%). The neck and arm VAS score were increased by over time. Conclusion : Long-term outcomes of ACDF with SAC group were acceptable but not satisfactory. For optimal decision making, more additional comparative long-term outcome data is needed between ACDF with SAC and ACDF with plating.

• 한국전자통신학회논문지
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• 제7권4호
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• pp.797-803
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• 2012

최근 독립된 네트워크의 구성 및 컨버전스 디바이스간 상호연결에 대한 요구로 MANET의 연구는 유비쿼터스 컴퓨팅 활용에 많은 주목과 고도의 성장을 보이고 있다. MANET에 참여하는 MN들은 호스트와 라우터 기능을 동시에 수행하여 네트워크 환경설정이 쉽고 빠른 대응력으로 임베디드 컴퓨팅에 적합하지만, 이동성으로 인한 동적 네트워크 토폴로지, 네트워크 확장성 결여 그리고 수동적 능동적 공격에 대한 취약성을 지니고 있어 지속적인 보안 서비스를 관리할 수 없다. 본 연구는 라우팅 단계에서 경로탐색 및 설정 시 악의적인 노드가 라우팅 메시지를 위 변조 하거나 적법한 MN으로 위장하는 공격을 방지하기 위해 AODV 라우팅 프로토콜에 MD5를 적용한 해시된 라우팅 프로토콜을 제안하여 안전성과 효율성을 개선하였다.

• 한국전자통신학회논문지
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• 제9권4호
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• pp.433-438
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• 2014

독립된 네트워크의 구성 및 컨버전스 디바이스간 상호연결에 대한 요구로 MANET의 연구는 유비쿼터스 컴퓨팅 활용에 많은 주목과 고도의 성장을 보이고 있다. MANET에 참여하는 이동노드들은 호스트와 라우터 기능을 동시에 수행하여 네트워크 환경설정이 쉽고 빠른 대응력으로 임베디드 컴퓨팅에 적합하지만, 이동성으로 인한 동적 네트워크 토폴로지, 네트워크 확장성 결여 그리고 수동적 공격, 능동적 공격에 대한 취약성을 지니고 있어 지속적인 보안 인증 서비스를 관리할 수 없다. 본 논문은 MANET의 무선 보안의 취약성과 현재 활용되고 있는 OTP S/Key와 DH-EKE를 분석하여, MANET 기반 강인한 인증을 위해 S-EKE 인증기법을 제안한다.

• 한국환경보건학회지
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• 제38권1호
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• pp.1-7
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• 2012

Carbon nanotubes (CNTs) stand at the frontier of nanotechnology and are destined to stimulate the next industrial revolution. Rapid increase in their production and use in the technology industry have led to concerns over the effects of CNT on human health and the environment. The prominent use of CNTs in biomedical applications also increases the possibility of human exposure, while properties such as their high aspect ratio (fiber-like shape) and large surface area raise safety concerns for human health if exposure does occur. It is crucial to develop viable alternatives to in vivo tests in order to evaluate the toxicity of engineered CNTs and develop validated experimental models capable of identifying CNTs' toxic effects and predicting their level of toxicity in the human respiratory system. Human lung epithelial cells serve as a barrier at the interface between the surrounding air and lung tissues in response to exogenous particles such as air-pollutants, including CNTs. Monolayer culture of the key individual cell types has provided abundant fundamental information on the response of these cells to external perturbations. However, such systems are limited by the absence of cell-cell interactions and their dynamic nature, which are both present in vivo. In this review, we suggested two viable alternatives to in vivo tests to evaluate the health risk of human exposure to CNTs.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.467-475
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• 2015

In this paper, the FREECAD 0.14 was used for modeling conventional Selfie-stick and the newly proposed Selfie-stick design. The purpose of this paper is to demonstrate the utility of FREECAD 0.14, which is open-source and still in development for further use. After modeling the conventional Selfie-stick, CatiyaV5 was used to assemble FREECAD 0.14 drawn elements. Main advance in newly designed Selfie-stick is the portability. To improve portability of the Selfie-stick, folding mechanism was adopted from folding LED stands. Several mechanisms were adopted to improve user convenience as well. Ansys 14.0 was used for structural analyses of conventional Selfie-stick model and the newly designed model as well. Several simplifications for the models were needed to process the analyses. When analyzing the newly designed model various materials were used one by one to find compatible composition. Using Aluminum alloys for the stick and the hand grip was found to be compatible. FREECAD was useful for suggestion of the newly designed model but not so much useful to design an actual product. Various efforts would make FREECAD the best choice for industrial use for free as it is named.