Command Shaping Control for Micro-milling Operations

Joel Fortgang,William Singhose,Juan de Juanes Márquez,Jesus Perez 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.6

Micro milling requires both high speed and high accuracy in order to economically produce parts with features on the scale of 1 μm. Micro mills are smaller and more flexible than traditional large-scale machines. Therefore, vibration of the machine structure is a significant problem. Given that micro milling requires high positioning precision, even small vibrations in the controller dynamics are problematic. The small-scale operation has considerably lower tool/workpiece interaction forces than traditional-scale milling. These low cutting forces have minimal effect on the machine structural re-sponse. Therefore, the dominant dynamic factor in exciting vibration can be the machine tool motion, rather than the workpiece/tool interaction. Given this realization, properly shaping the motions of the micro mill is a promising approach to reduce vibration. This paper presents a nonlinear command-shaping technique to reduce the vibrations of a micro mill that can be implemented with a standard CNC controller. The robustness of this technique to modeling errors and disturbances is investigated. Theoretical proofs and experimental demonstrations of the command-shaping technique are presented. The improved performance from the command shaping enables higher throughput and improved accuracy of the micro mill.

Reactivity of hydroxyl radicals with neonicotinoid insecticides: mechanism and changes in toxicity

Dell'Arciprete, Maria L.,Santos-Juanes, Lucas,Sanz, Antonio Arques,Vicente, Rafael,Amat, Ana M.,Furlong, Jorge P.,Martirea, Daniel O.,Gonzalez, Monica C. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.7

The reactivity of hydroxyl radicals ($HO^{\cdot}$) towards three neonicotonoid insecticides, namely imidacloprid, thiacloprid and acetamiprid was investigated. These radicals were generated by photolysis of $H_2O_2$ solutions. Flash photolysis experiments were used to determine the rate constants of $5.5{\times}10^{10}M^{-1}s{-1}$, $6{\times}10^{10}M^{-1}s^{-1}$, and $7.5{\times}10^{10}M^{-1}s^{-1}$, for the reactions of $HO^{\cdot}$ with acetamiprid, imidacloprid, and thiacloprid, respectively. Continuous irradiation experiments in the absence and presence of $H_2O_2$ allowed the identification and toxicity evaluation of the primary photo- and oxidation products of the insecticides. In all cases, the less toxic 6-chloronicotinic acid was found to be the major product at higher degrees of oxidation. The results reported here indicate that the half life of the insecticides due to their reaction with $HO^{\cdot}$ radicals in natural aquatic reservoirs may vary between 5 h and 19 days, and therefore the hydroxyl radical-mediated oxidation may be a significant abiotic elimination route. However, elimination of the insecticide under such conditions might not improve the quality of the contaminated water, as the primary products of degradation still show considerable toxicity to Vibrio fischeri assays.

Maximizing the value of pressure data in saline aquifer characterization

Yoon, Seonkyoo,Williams, John R.,Juanes, Ruben,Kang, Peter K. Elsevier 2017 Advances in water resources Vol.109 No.-

<P><B>Abstract</B></P> <P>The injection and storage of freshwater in saline aquifers for the purpose of managed aquifer recharge is an important technology that can help ensure sustainable water resources. As a result of the density difference between the injected freshwater and ambient saline groundwater, the pressure field is coupled to the spatial salinity distribution, and therefore experiences transient changes. The effect of variable density can be quantified by the mixed convection ratio, which is a ratio between the strength of two convection processes: free convection due to the density differences and forced convection due to hydraulic gradients. We combine a density-dependent flow and transport simulator with an ensemble Kalman filter (EnKF) to analyze the effects of freshwater injection rates on the value-of-information of transient pressure data for saline aquifer characterization. The EnKF is applied to sequentially estimate heterogeneous aquifer permeability fields using real-time pressure data. The performance of the permeability estimation is analyzed in terms of the accuracy and the uncertainty of the estimated permeability fields as well as the predictability of breakthrough curve arrival times in a realistic push-pull setting. This study demonstrates that injecting fluids at a rate that balances the two characteristic convections can maximize the value of pressure data for saline aquifer characterization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First-time application of Ensemble Kalman filter to a saline coastal aquifer. </LI> <LI> We elucidate the variable-density effect on the value of pressure data. </LI> <LI> The effect of variable density can be quantified by the mixed convection ratio. </LI> <LI> The value of pressure data is maximized at the balanced mixed convection regime. </LI> <LI> The density effect on the value of data decreases as heterogeneity increases. </LI> </UL> </P>

Emergence of anomalous transport in stressed rough fractures

Kang, P.K.,Brown, S.,Juanes, R. North-Holland Pub. Co ; Elsevier Science Ltd 2016 Earth and planetary science letters Vol.454 No.-

We report the emergence of anomalous (non-Fickian) transport through a rough-walled fracture as a result of increasing normal stress on the fracture. We show that the origin of this anomalous transport behavior can be traced to the emergence of a heterogeneous flow field dominated by preferential channels and stagnation zones, as a result of the larger number of contacts in a highly stressed fracture. We show that the velocity distribution determines the late-time scaling of particle spreading, and velocity correlation determines the magnitude of spreading and the transition time from the initial ballistic regime to the asymptotic anomalous behavior. We also propose a spatial Markov model that reproduces the transport behavior at the scale of the entire fracture with only three physical parameters. Our results point to a heretofore unrecognized link between geomechanics and particle transport in fractured media.

Anomalous transport in disordered fracture networks: Spatial Markov model for dispersion with variable injection modes

Kang, Peter K.,Dentz, Marco,Le Borgne, Tanguy,Lee, Seunghak,Juanes, Ruben C.M.L. Publications 2017 ADVANCES IN WATER RESOURCES Vol.106 No.-

<P><B>Abstract</B></P> <P>We investigate tracer transport on random discrete fracture networks that are characterized by the statistics of the fracture geometry and hydraulic conductivity. While it is well known that tracer transport through fractured media can be anomalous and particle injection modes can have major impact on dispersion, the incorporation of injection modes into effective transport modeling has remained an open issue. The fundamental reason behind this challenge is that—even if the Eulerian fluid velocity is steady—the Lagrangian velocity distribution experienced by tracer particles evolves with time from its initial distribution, which is dictated by the injection mode, to a stationary velocity distribution. We quantify this evolution by a Markov model for particle velocities that are equidistantly sampled along trajectories. This stochastic approach allows for the systematic incorporation of the initial velocity distribution and quantifies the interplay between velocity distribution and spatial and temporal correlation. The proposed spatial Markov model is characterized by the initial velocity distribution, which is determined by the particle injection mode, the stationary Lagrangian velocity distribution, which is derived from the Eulerian velocity distribution, and the spatial velocity correlation length, which is related to the characteristic fracture length. This effective model leads to a time-domain random walk for the evolution of particle positions and velocities, whose joint distribution follows a Boltzmann equation. Finally, we demonstrate that the proposed model can successfully predict anomalous transport through discrete fracture networks with different levels of heterogeneity and arbitrary tracer injection modes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Injection modes have major impact on anomalous transport in DFNs. </LI> <LI> Evolution of the Lagrangian velocity distribution is governed by injection modes. </LI> <LI> Spatial velocity Markov model for variable injection modes. </LI> <LI> Equivalence between spatial Markov model and Boltzmann equation. </LI> </UL> </P>

河南方言使用现状调查及展望

陈娟 ( Chen¸ Juan ),罗敏球 ( Na¸ Mingu ) 중국학연구회 2020 중국학연구 Vol.- No.94

이 논문은 하남성에서 사용하고 있는 방언의 사용 상황을 조사하고 검토하였다. 우선 하남 방언을 중심으로 했던 사회언어학연구를 살펴보고 본 연구의 의미를 밝히었다. 그 다음 설문 조사의 형식을 통해 현재 거주지、연령、교육정도 등 기준으로 사용 장소、교류대상、언어 태도 등을 분석하였으며, 이를 바탕으로 하남방언과 보통화의 사용 현황 및 하남방언 사용자들의 언어태도를 진단하였다. 조사 결과에 따르면, 보통화와 방언의 우열은 사용 환경 및 사용 집단에 따라 변화한다는 점 그리고 방언사용자 비율이 교육 정도와 밀접하게 연관돼 있다는 것을 발견하였다. 교육 수준이 높을수록 방언을 사용하는 비율이 낮았다. 같은 방언을 사용하는 대상자와 교류할 때에도 보통화를 쓰는 현상은 일상 언어 환경이나 언어습관 때문일 수 있지만, 보통화의 영향을 받아 방언 사용율이 감소하였을 것이라고 판단된다. 언어태도 조사에 따르면, 방언에 대해 긍정적인 태도를 가진 비율이 낮은 편이고 보편적으로 보통화가 더 가치가 있다고 생각해서 자신의 아이들에게 보통화를 배우게 하는 경향도 나타났다. 방언의 미래에 대해 물어 봤을 때 조사 대상자들은 ‘둘 다 공존할 것이다’라는 답이 가장 많았다. 마지막으로 언어 외부 요인 즉 보통화 보급 정책、매스컴 전파 방식、방언 사용자들의 언어 태도로 인해 하남방언이 점점 보통화와 거리를 좁혀가고 있음을 알 수 있었다. Starting with the three social variables of current residence, age, and education level, this article examines the current status of using Henan dialect and the attitude of native dialect speakers by conducting surveys focusing on key contents such as use scenario and language attitude. Analysis showed that not only college or higher but also all residents and age groups currently residing in social variables tend to use Mandarin during official events. In this case Mandarin becomes the dominant language, and in informal settings all social variables prefer to use Henan dialect, but at this time Henan dialect becomes the dominant language. It can be seen that language strengths are not fixed and will change with changes in the use environment. This article analyzes the content and reason of Henan dialect’s tendency to approach in Mandarin. This tendency is mainly reflected in the weakening of dialectic characteristics, the contraction of group use. The cause of this phenomenon is mainly the external element of language, namely the promotion of mandarin. Three aspects of media communication methods and the language attitude of native dialect speakers are analyzed. Also, based on the results of existing research in dialect, this article believes that the reduction of dialect will bring about the situation of language integration in China, but this does not help balance cultural diversity. To protect and inherit Henan dialect and maintain the coexistence of Mandarin, certain measures are needed to avoid the process of language integration and maintain cultural diversity and culture in three aspects of national policy, social organizations and individuals.

La evolución poética de Pablo Neruda y el surrealismo

Bahk, Juan-W 서울대학교 스페인중남미연구소 2005 이베로아메리카硏究 Vol.16 No.-

A través del análisis de varios poemas de Residencia en la tierra, La evolución poética de Pablo Neruda y el surrealismo no sólo se ha procurado seguir la gestación de la poesía surrealista del poeta sino que también se ha tratado de verificar la existencia de las características surrealistas en sus obras. Su autor ha querido también mostrar los discursos poéticos provenientes de la nueva poética naciente en España de aquel entonces, ya que por la amistad que tenía con los poetas del grupo poético del 27, Neruda estaba al tanto del cambio de la flamante poesía. Otro aspecto del que no podemos prescindir es que Neruda a los 15 años era conocedor del idioma francés y por ello leía las obras de Apollinaire, Rimbaud y Baudelaire; o sea, Neruda seguía teniendo contacto con los grandes precursores franceses cuyas contribuciones aportaron al nacimiento de la poesía vanguardista del siglo XX. Este estudio es un proceso ininterrumpido de la evolución poética de Pablo Neruda. Todo lo que tenía en su fondo personal, desde su origen humilde como el hijo de un ganadero y ferroviario hasta su carrera política como senador de Chile y cónsul en varios países de cuatro continentes, llega a cuajar muy bien con la constante evolución de su poética. Este trabajo ha trazado el trayecto de Neruda desde su inicio hasta Residencia en la tierra con el objetivo de que entendamos mejor su poesía surrealista.

임란기(壬亂期) 의병문인이 바라 본 남송 ― <영남송사(詠南宋史)>의 주제의식 및 그 시적 형상화

田娟 ( Tian¸ Juan ) 성균관대학교 대동문화연구원 2020 大東文化硏究 Vol.112 No.-

<영남송사>는 임진왜란 당시 의병으로 참여했던 剡湖 陳景文이 ‘미개국에 의해 짓밟힌 문명국’이라는 남송의 ‘신화’의 중복과 재구를 통해 전쟁의 상처를 투영하고 폐허 속에서 다시 일어서기 위한 의지를 표출하고자 쓴 장편 연작 영사시다. 본고는 이 작품의 창작 배경과 주제적·예술적 특징 등을 살펴보았다. <영남송사>는 칠언절구로 이루어진 총 69수의 연작시이다. 그 내용은 79명의 역사적 인물에 대한 형상화와 ‘고종화의’라는 역사적 사건을 중심으로 다루고 있다. 본고에서는 작품 속 인물을 남송의 군주, 남송의 臣·民, 금·원 출신의 인물 등의 세 가지로 분류하여 살폈다. 이를 통해 이 작품이 ‘오랑캐 문제에 대한 대응’에 초점을 맞추고 있음을 알 수 있으며, 임진왜란으로 인한 심리적 충격과 함께 군주의 덕목, 忠義 정신, 華夷觀 등에 관한 작자의 생각 등을 살필 수 있다. 본 작품의 예술적 특징을 두 가지의 측면에서 살펴보았다. 우선 여러 작품으로 이룬 하나의 전체로 볼 때 비교적 치밀한 짜임새를 갖추고 있다. 분명한 포커스의 존재, 종적 축과 횡적 폭의 상호 작용을 통해, 개별 작품이 조직적·유기적으로 묶이어 정밀한 구조를 갖춘 하나의 결합체를 형성하여, 작품의 완결성을 확보하였다. 다음으로 <영남송사>를 이루는 개별 작품을 한 편 한 편 살펴보았을 때, 특별한 기교와 수법없이 그저 자신의 평가와 감정을 직설적이고 소박하게 털어놓는 방식을 사용하여 분명한 가치 판단과 강렬한 감정을 효과적으로 전달하였다. 이러한 두 가지 방식의 조화로운 결합, 거기에 전달하고자 하는 생각과 감정의 진솔함을 더하였기 때문에, 이 작품은 감정과 메시지 전달에 큰 성공을 거두었다. On the History of Southern Song Dynasty is a series of poems on history written by Jin Kyungmun who participated in Korean voluntary soldier movement during the Japanese invasion period in Year RenChen (29th year of the Sexagenary Cycle). There are 69 poems in total and all of them are four-line poems with seven characters per line and express the praises and demerits of historical figures in Southern Song Dynasty. Firstly, the poet's specific evaluations on the emperors, ministers, citizens, and people of Jin Dynasty are reviewed. The results show that both the choice of specificallydescribed objects and the evaluations of merits and demerits mainly focus on the dealing methods of foreigners, which should be the reflection of metaphor literature of psychological impact brought by the Japanese invasion in Year RenChen. Secondly, the artistic techniques and literary effects of this work are reviewed from two perspectives, the poems as a whole and the individual works in this work.

Surf points based Moving Target Detection and Long-term Tracking in Aerial Videos

( Juan-juan Zhu ),( Wei Sun ),( Bao-long Guo ),( Cheng Li ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.11

A novel method based on Surf points is proposed to detect and lock-track single ground target in aerial videos. Videos captured by moving cameras contain complex motions, which bring difficulty in moving object detection. Our approach contains three parts: moving target template detection, search area estimation and target tracking. Global motion estimation and compensation are first made by grids-sampling Surf points selecting and matching. And then, the single ground target is detected by joint spatial-temporal information processing. The temporal process is made by calculating difference between compensated reference and current image and the spatial process is implementing morphological operations and adaptive binarization. The second part improves KALMAN filter with surf points scale information to predict target position and search area adaptively. Lastly, the local Surf points of target template are matched in this search region to realize target tracking. The long-term tracking is updated following target scaling, occlusion and large deformation. Experimental results show that the algorithm can correctly detect small moving target in dynamic scenes with complex motions. It is robust to vehicle dithering and target scale changing, rotation, especially partial occlusion or temporal complete occlusion. Comparing with traditional algorithms, our method enables real time operation, processing 520×390 frames at around 15fps.

Clinical and Pathological Characteristics of Intraocular Cysticercosis

Juan-Juan Li,Li-Wei Zhang,Hua Li,Zhu-Lin Hu 대한기생충학열대의학회 2013 The Korean Journal of Parasitology Vol.51 No.2