• Journal of Information Processing Systems
• /
• 제16권1호
• /
• pp.42-48
• /
• 2020

This paper proposes an operating system architecture for unmanned aerial vehicle (UAV), which is secure against root exploit, resilient to connection loss resulting in the control loss, and able to utilize common applications used in Linux. The Linux-based UAVs are exposed to root exploit. On the other hand, the microkernel-based UAVs are not able to use the common applications utilized in Linux, even though which is secure against root exploit. For this reason, the proposed architecture uses a virtualized microkernel on the Linux operating system to isolate communication roles and prevent root exploit. As a result, the suggested Operating system is secure against root exploit and is able to utilize the common applications at the same time.

• 한국조경학회지
• /
• 제28권4호
• /
• pp.1-8
• /
• 2000

This study is conducted to evaluate the effects of root restriction on growth of maple(Acer palmatum Thumb.). Tow types of container such as clay pot(CP), root control bag(RCB) were used to restrict maple's root and each type of container was divided into 5 sizes. The containers with plants were buried just below the soil level and maples planted directly in the soil (nonrestricted root treatment) were included as comparison. Data were collected on dry weight of leaf, trunk, thick root, rootlet and soil water potential. We have analyzed, simple linear regression, Pearson's Correlation analysis, Duncan's multiple rang test, and Covariance Analysis using SAS statistical software. The results of analysis based on these data are as follows; 1. Total dry weight of maple in CP was significantly larger than in RCB. 2. Difference in growth reduction by the kinds of containers was induced by different hydraulic diffusion ratios between container and soil. Difference in growth reduction by the size of container was induced by the difference density of rootlet and soil moisture contents in the container. 4. Commercial products of root control of root control bag appeared not proper for countries in which fluctuation of rainfall is severe. Because maples in RCB were restricted by excess soil water in the rainy season, or by lack of soil water in the dray season.

• Journal of Welding and Joining
• /
• 제26권6호
• /
• pp.97-102
• /
• 2008

It is well known that there exist two typical fatigue crack initiation locations in ship structures: one is the weld toe and the other is the weld root where partial penetration weld is performed. In particular, it is important for fillet weldments to avoid weld root cracking in order to prevent catastrophic failure particularly in ship structures. Therefore detail considerations are required for cruciform joints with partial penetration when there is a possibility of weld root crack initiation. For these reasons, fatigue tests on welded joints were performed in this study. Concept of stress intensity factor(SIF) by means of fracture mechanics is applied for predicting fatigue life of fillet welded joints.

• 한국환경복원기술학회지
• /
• 제6권3호
• /
• pp.69-78
• /
• 2003

The main purpose of this study was to verify the shore margin protection effect of the root system of Salix gracilistyla Miq. developed from direct sticking cuttings on wetland, focusing on the effect of the root system reducing soil particle dissociation rate in water. The soil dissociation rate was examined through slaking tests with cylindric pure soil column at maximum particle density and the same size column of root reinforced soil. The dry weight of remained soil was measured after 5, 10, 15, 30minutes and 1, 6, 12, 24, 48hours inundation. As results, the soil particles began to dissociate severely at 10 minutes and only 10% of soil particles were left after 25minutes inundation. The stable slope angle of pure soil was $36^{\circ}$after 24 hours. On the other hand, the columns of root reinforced soil were stable even after 24hours, being dissociated only 7.2% of soil particles. So, it was revealed that the root system was very effective materials protecting more than 80% of soil particle from dissociation in inundation.

• 대한조선학회논문집
• /
• 제48권1호
• /
• pp.56-61
• /
• 2011

In this study, a series of fatigue tests was conducted to evaluate fatigue strength for the root gap difference with high strength steel with butt welded joints. A finite element analysis using effective notch stress method was also performed to compare effective notch factors each other with butt welded specimens made by copper backing. The results of fatigue tests were classified according to the root gap difference. Fatigue life of butt welded specimens is presented for determining the root gap of high strength steel with butt welded joints in terms of fatigue strength. Then effective notch stress was applied to interpret fatigue strength of butt welded specimen model which is reflected actual measured dimensions. As a result, fatigue strength of high strength steel with butt welded specimens is increased by root gap gets longer in length.

• 한국작물학회지
• /
• 제66권4호
• /
• pp.452-458
• /
• 2021

뿌리는 식물에서 양분과 수분을 흡수하는 가장 중요한 기관임에도 불구하고 분석방법에 어려움으로 인해 지상부에 비해 연구가 상대적으로 미비한 실정이다. 최근 이미지를 기반으로 작물의 표현형을 분석하는 기술이 급격하게 발달하고 있으며, 뿌리 연구에 있어서도 이미지를 다양하게 활용하고 있다. 뿌리분석은 목적에 따라 토양에서 분리 후 측정하는 방법과 토양에서 바로 측정하는 방식이 있으며, 각각의 방식들마다 장점과 단점이 있으므로 연구자의 상황에 맞게 활용할 수 있다. 이런 이유에서 본 리뷰에서는 이미지를 활용한 뿌리분석 방법들에 대해 소개하여 국내 연구자들의 뿌리 연구에 이용되기를 바란다.

• 한국조경학회지
• /
• 제31권6호
• /
• pp.77-84
• /
• 2004

This study was carried out to analyze the vertical and horizontal distribution of fine root biomass of Pinus thunbergii transplanted in reclaimed land from the sea near Gwangyang Bay. The fine-root biomass according to 6 planting ground types were as follows: 98.5 g DM/$m^2$ for P2, 51.1 g DM/$m^2$ for P6, 47.8 g DM$m^2$ for P5, 44.6 g DM/$m^2$ for P3, 38.2 g DM/$m^2$ for P4, 31.8 g DM/$m^2$ for Pl, respectively. The vertical distribution of fine root biomass decreased at descending soil depths of the 6 mounding types. Fine root biomass was 31∼55% in the topsoil of 20cm depth. Fine root biomass that were related to the Spatial distance from the nearest tree were unevenly distributed horizontally in 6 stands. distribution patterns of fine root biomass were closely related to soil hardness and alkalic cation (Ca++, Mg++, Na+, K+) concentrations. Therefore, in order to have good condition for the growth of landscaping plants, we suggest that there is a need for the construction of planting grounds as well as a need for soil improvement in bad soil environments.

• 대한전자공학회논문지SD
• /
• 제46권3호
• /
• pp.20-25
• /
• 2009

본 논문에서는 모바일 환경 기반의 3차원 그래픽 연산을 위한 조명처리 엔진 및 쉐이더 프로세서에 사용 가능한 제곱근과 역제곱근 연산기의 구조를 제안한다. 제안하는 구조는 Taylor 전개식을 기반으로 하여 참조 테이블 및 보정 유닛으로 구성되어 있어 참조 테이블의 크기를 줄였다. 연산 결과는 IEEE-754 표준의 단정도 32 bit 부동소수점 형식과 모바일 환경을 위하여 이를 축소한 24 bit 부동소수점 형식에 대해 OpenGL 1.x ES 에서 요구하는 $10^{-5}$의 정확도를 거의 만족한다. 제안된 구조에 따라 설계된 제곱근 및 역제곱근 연산기는 Verilog-HDL을 사용하여 설계되었으며 파라미터 변경을 통하여 24 bit와 32 bit 연산이 가능하도록 합성이 가능하고 1사이클의 잠복기를 갖는다. 설계된 연산기들의 동작은 FPGA를 이용한 검증시스템을 통하여 검증하였다.

• 한국조경학회지
• /
• 제31권5호
• /
• pp.1-10
• /
• 2003

The purpose of this study was to verify the shore margin protection effect of a root system developed from direct sticking of Salix gracilistyla Miq., focusing on the reinforcement of soil shear strength. The materials were 20cm long sticks whose average diameter and weight were 7.52mm and 14.58g respectively, and sandy loam(Sand 60.36%, Silt 28%, Clay 11.64%), whose maximum dry weight(${\gamma}$$_{dmax}$) was 1.59gf/㎤ at the water ratio( $W_{opt}$) 13.8%. The direct shearing test(KS F 2343) was applied to cylindric columms(diameter 132mm) of pure soil and two years old root reinforced soil. At each condition of vertical stress, 10N/$ extrm{cm}^2$, 14.41N/$\textrm{cm}^2$ and 18.82 N/$\textrm{cm}^2$, five soil+root columns were sheared. After shear tests, the root area ratio and soil moisture on the shear plane were measured. The results of this research were as follows: 1. The average of root area ratio was 1.86% and the soil moisture 14.67%. 2. Two years old root system was found to increase the soil shear strength of pure soil in terms of Cohesion(C) and Inner friction Angle($\phi$) as follows. 3. The relationship between root area ratio and the increased shear strength can be presented with the following equation, $\Delta$S ≒ 0.33ㆍ TrㆍAs/A $\Delta$S : Increased Shear Strength Tr : Average Tension Strength of Root, Ar/A : Root Area Ratioioage Tension Strength of Root, Ar/A : Root Area Ratio

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.174-174
• /
• 2017

To cope with phosphate (Pi) deficient stress, plants modulate various physiological and developmental processes, such as gene expression, Pi uptake and translocation, and root architecture changes. Here, we report the identification and characterization of novel activation-tagged mutant involved in Pi starvation signaling in Arabidopsis. The hpd (${\underline{h}ypersensitive}$ to ${\underline{P}i}$ $ {\underline{d}eficiency}$) mutant exhibits enhanced phosphate uptake and altered root architectural change under Pi starvation compared to wild type. Expression analysis of auxin-responsive DR5::GUS reporter gene in hpd mutant indicated that auxin translocation in roots under Pi starvation are suppressed in hpd mutant plants. Impaired auxin translocation in roots of hpd mutant was attributable to abnormal root architecture changes in Pi starvation conditions. Our results indicated that abnormal auxin translocation in hpd mutant might be due to mis-regulation of auxin efflux carrier proteins, PIN-FORMED (PIN) 1, and 2 under Pi starvation conditions. Not only expression levels but also expression domains of PIN proteins were altered in hpd mutant in response to Pi starvation. Molecular genetic analysis of hpd mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3'-end processing. The results suggest that mRNA processing plays crucial roles in Pi homeostasis as well as developmental reprograming in response to Pi deprivation in Arabidopsis.