• 제목/요약/키워드: Absolute position

검색결과 399건 처리시간 0.029초

Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

  • Nikneshan, Sima;Aval, Shadi Hamidi;Bakhshalian, Neema;Shahab, Shahriyar;Mohammadpour, Mahdis;Sarikhani, Soodeh
    • Imaging Science in Dentistry
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    • 제44권4호
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    • pp.257-262
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    • 2014
  • Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., $0^{\circ}$), $+10^{\circ}$, $+12^{\circ}$, $-12^{\circ}$, and $-10^{\circ}$ with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of $-12^{\circ}$, -0.66 to -0.11 at $-10^{\circ}$, -0.51 to +0.19 at $0^{\circ}$, -0.64 to +0.08 at $+10^{\circ}$, and -0.64 to +0.1 at $+12^{\circ}$. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of $-12^{\circ}$ to $+12^{\circ}$ reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

기준점 측량을 활용한 광파기 기반 댐 제체 변위 계측 신뢰도 향상 (Improving Reliabilities of Dam Displacement based on Monitoring Given Points by Total Station)

  • 강기천;김봉재;홍석우;임연출;김지성
    • 한국지반신소재학회논문집
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    • 제16권1호
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    • pp.1-8
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    • 2017
  • 댐 변위 모니터링은 댐의 안전성을 위협하는 영향을 파악하여 댐과 관련된 붕괴사고를 사전에 방지하고, 댐을 안전하게 운영하고 유지 관리하는데 중요한 항목으로 사용되고 있다. 하지만, 기존 변위계측 분석 결과 원인불명의 변위가 발생하여 정확한 댐 거동 해석을 저해하고 있다. 본 연구에서는 광파기(Total Station) 기반 댐의 변위계측의 신뢰성 개선을 위해 그 보정방법을 제안하였다. 현재까지의 광파기에 의한 변형 모니터링은 기준점(2~3개소)과 광파기가 설치된 기계점 위치를 초기에 측량하여 불변으로 간주하였고, 측량과정에서 중요한 변위 산정요소가 되는 기준 수평 수직각은 고려하지 않고 측량을 실시하였다. 본 연구에서는 실제 댐 변위 계측시 기준점 측량을 통해 광파기의 위치 변화 및 기준 수평 수직각의 변화를 관측하였다. 그 결과 오차발생의 가장 큰 원인은 광파기 위치 변화와 댐 변위량 계산에 중요한 항목인 기준 수평 및 수직각임이 밝혀졌다. 또한, 이를 보정한 결과 최대 변위 20mm에서 약 ${\pm}5mm$로 감소하였다.

웹다큐멘터리의 재현양식과 리얼리티에 관한 연구 (Study on the Representation Modes and Reality of Web Documentaries)

  • 전경란
    • 만화애니메이션 연구
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    • 통권45호
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    • pp.259-282
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    • 2016
  • 다큐멘터리는 영화에서 텔레비전, 그리고 다양한 디지털 미디어를 거치며 새로운 장르 형식으로 재탄생되고 있으며, 웹다큐멘터리는 그 대표적 사례라 할 수 있다. 웹다큐멘터리는 제작자와 이용자에 의해 구성되는 다큐멘터리로, 이용자의 상호작용이 절대적인 새로운 유형의 텍스트이다. 이 연구에서는 <석탄 끝으로의 여행(Journey to the End of Coal)>과 <프리즌 밸리(Prison Valley)> 등 두 편의 웹 다큐멘터리에 대한 분석을 통해 웹다큐멘터리가 웹이 표현매체로서 지닌 특징들을 어떻게 활용하여 이용자로 하여금 현실을 체험하도록 유도하고 있는지 살펴보았다. 웹다큐멘터리는 이용자의 상호작용을 허용하는 이중적, 공간적 구조라는 특징을 지니고 있으며, 백과사전적 특징과 같은 특징을 기반으로 이용자에게 현실에 대한 다양한 정보와 지식에 직접 대면토록 한다. 또한 웹다큐멘터리는 이용자에게 다큐멘터리를 진행시키고 텍스트를 확장하는 역할을 부여함으로써 현실을 탐구해가는 주체로서의 의식을 자극하는 형식을 띠고 있다. 이 과정에서 웹다큐멘터리의 이용자는 다큐멘터리가 제안하는 현실을 비판적으로 성찰하고 그 이면의 의미를 포착할 수 있는 가능성을 갖는다. 이러한 특징들은 웹다큐멘터리를 현실을 추구하는 방식은 물론 그것이 지닌 의미에 있어서 전통적인 다큐멘터리와 차별화된 텍스트로 만들어주는 것이다. 이 때문에 웹다큐멘터리 현상의 혁신적인 지위는 분명해지며, 웹다큐멘터리에 대한 논의의 필요성이 제기된다고 하겠다. 웹다큐멘터리는 단순히 새로운 미디어 기술 현상을 넘어 전통적인 다큐멘터리에 대한 근본적인 도전이라는 의미를 갖는다.

올바른 RGP렌즈의 처방과 관리용품의 사용에 대한 결과 연구 (Studies on Corrected RGP Lens Fitting and Use of Care System)

  • 성정섭;홍수학
    • 한국안광학회지
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    • 제5권2호
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    • pp.59-64
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    • 2000
  • 각막골률계로 측정한 결과 각막난시가 최소한 0.75D 이상인 58명을 선정하여 RGP 구면렌즈를 3개월간 착용시켜 조사했는데 이 중 35명은 각막난시가 1.50D 이상이었다. 환자의 방문 스케줄은 대상자를 시력검사, 각막 굴절력(K값) 및 세극등 현미경 검사로 적합한 렌즈를 피팅한 다음, 1주일, 그 후 1개월 간격으로 방문하게 하여 검사하였는데 방문할 때마다 렌즈를 착용한 시력검사, overrefraction, overkeratometry 및 세극등 검사를 하고 렌즈의 움직임, 렌즈의 위치와 렌즈의 표면상태 등을 기록했다. 대상자 전원을 착용기간에 세극등으로 CCC(central corneal clouding) 분류한 결과 각막부종과 신생혈관은 전혀 나타나지 않았다. 각막에 플루오레션 stain 반응을 한 결과 52명이 grade 0.5 상태를 보였고, 5명이 grade 1 및 1명이 grade 2로 판정되었다. Overrefraction에서 렌즈를 착용하기전과 착용후의 잔류난시는 처음 피팅할 때는 41%, 1주일 후는 34%, 1개월 후는 30%, 2개월 후는 29%로 나타난 결과로 보아 1개월 이후는 변화가 거의 없음을 알 수 있었다. 절대 굴절력에서 평균 overrefraction은 처음 피팅했을 때는 0.26D이었고, 1주일 후는 0.22D, 1개월 후는 0.17D 및 2개월 후는 0.16D를 보였다. 또한 관리용액은 다목적 용액을 주로 사용하고 있었고 각 용도에 맞는 용품에 비해 그 기능이 저하됨을 알았다.

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소형 계수용 및 영상용 감마프로브 시스템의 설계와 성능평가 (Design and Performance Evaluation of Small Size Counting and Imaging Gamma Probe System)

  • 양묘근;곽철은;심용걸;김희중;최용;정준기;이명철;고창순
    • 대한의용생체공학회:의공학회지
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    • 제18권3호
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    • pp.291-299
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    • 1997
  • As a microimaging device detecting gamma rays emitted from small lesions or tumors during operation, the intraoperative surgical probe has been proposed and is now under development. We have designed a multipurpose portable gamma prove system and evaluated the performance both for the absolute counting purpose of residual radioactivities and for the localizing capability of gamma events using the NaI(Tl) crystal and two types of photomultiplier tubes(PMTs). Counting efficiencies in the range of routine clinical use of radiation dose were measured using the assembly of single channel PMTs and 0.5 inch thick NaI(Tl) crystal of 1 inch diameter. The positioning of gamma events for imaging purpose requires the multiple channel PMTs with appropriate positioning electronics. We have designed a simple and reliable positioning circuit based on the concept of modified Anger. In preliminary experiments using the multiple channel PMT of 3 inch diameter and the dim lighth source, we were able to trace and localize the correct position with reduced positioning error by the use of two multiplier/divider chipset and simplified peripherals. The energy resolutions for the counting gamma probe measured as full width at half maximum(FWHM) for Cs-137, F-18, Tc-99m were 12%, 13%, and 36%, respectively. The spatial resolution for the imaging gamma probe measured as FWHM for green LED was 2.9 mm. The results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine. Future studies will include developing collimators, improving interface hardwares, and evaluating the system with clinical data.

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돼지 FABP3 Promoter 부위 내 신규 돌연변이 탐색과 근내지방도와의 연관성 분석 (Detection of Novel Mutations in the FABP3 Promoter Region and Association Analysis with Intramuscular Fat Content in Pigs)

  • 김재환;박응우;박정진;최봉환;김태헌;서보영;정일정;임현태;오성종;이정규;전진태
    • Journal of Animal Science and Technology
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    • 제47권1호
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    • pp.1-10
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    • 2005
  • Intramuscular fat content(lMF) is considered as one of major economic traits in the pig breeding and industry. In general, high IMF results in better meat quality. Several approaches to detect quantitative trait 10ci( QTL) for IMF indicated a strong possibility of the existence of a QTL related to IMF between the microsatellite marker SW71 and SW1881 on SSC6q. Porcine FABP3 has been considered as a candidate gene affecting IMF due to its physiological roles and position on the pig genome. Two novel mutations, g.-114T> C and g.-158T>G were detected by duplicate sequencing of the porcine FABP3 promoter region. These two mutations were identified as absolute linkage disequilibrium. The g.-158T> G mutation was used for investigating relationships with growth and fat deposition traits. The GG genotype of the g.-158T> G polymorphism showed highly negative effects(P< 0.01) on body weights at 3 and 12 weeks of age, and a positive effect(P< 0.05) on IMF. However, backfat thickness(BF) and carcass fat(CF) content were not significantly associated with the genotype. The result indicates that the novel mutations, identified in this study, could be utilized as possible genetic markers to improve IMF, independent with BF.

루드빅 볼츠만의 과학 방법론에 대한 역사-비판적 검토 (Critics on Ludwig Boltzmann's Methodology of Science)

  • 문장수;이우붕
    • 철학연구
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    • 제117권
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    • pp.57-84
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    • 2011
  • 본 연구는 루드빅 볼츠만의 과학 방법론 및 물리학적 인식들에 대한 인식론적 지위 문제를 역사-비판적으로 검토한다. 잘 알다시피, 그는 열역학의 확률론적 해석을 통해 통계 물리학의 발판을 마련했을 뿐만 아니라, 과학 방법론에 대한 많은 논문들을 발표했고 직접 철학을 강의하기도 했다. 그러나 물리학의 인식론에 대한 그의 입장은 실재론과 현상론, 유물론과 관념론, 절대적 진리관과 상대적 진리관 사이에서 배회했다. 이에 본 연구에서는 과학사 및 과학 철학의 관점에서 19 세기 말에서 20 세기 초에 걸쳐 전개된 물리학의 방법론 및 인식론들에 대한 다양한 논쟁들을 비판적으로 검토하면서 볼츠만의 이러한 배회의 배경을 해명하면서 동시에 그에게서 볼 수 있는 일관된 과학방법론 및 인식론을 도출하여 재구성하려고 노력할 것이다. 단정적으로 말하면, 우리는 그것을 '정신-물체 동일성 이론'으로 특성화하면서, 아울러 이러한 동일성 이론은 작금의 물리학적 인식론의 바람직한 한 형태가 될 수 있다는 것을 정당화하려고 노력할 것이다.

여자의 사랑, 행위 그리고 정치 - 와즈디 무아와드의 <그을린 사랑> - (A Study on Wajdi Mouawad's 'Incendies' based on Lacanian Thoughts of the Woman)

  • 김숙현
    • 한국연극학
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    • 제53호
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    • pp.57-87
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    • 2014
  • This article re-reads the messages of the text, 'Incendies', the uncanny actions and the strange words of protagonist Nawal, through the ideas of Jacques Lacan, particularly his notion of sexuation with posing questions about most of the previous reviews which are based on femininity or motherhood. For Lacan, masculinity and femininity are not biological essences but symbolic positions, and the assumption of one of these two positions is fundamental to the construction of subjectivity. So 'man' and 'woman' are merely signifiers that stand for these two subjective positions. Each side is defined by both an affirmation and a negation of the phallic function, by both an inclusion and exclusion of absolute non-phallic jouissance. Unlike the man, the woman is 'not-all' identified with the phallic function, demonstrating the undecidability and impossibility of totalising the woman. Although the woman is bound to do castration through being subject to the phallic function, she is also related to the signifier of the barred Other, S(Ⱥ) which stands for a gap or lack in the Other. Thus, as a consequence of not being entirely within the symbolic, she has an Other Jouissance, Feminine Jouissance, because it's possible to face emptiness of the Symbolic, the Real only in the place of the woman for new Ethics/Politics. This paper finds that Nawal is not completely defined by the phallic function and she is a subject of death drive that practices the signifying cut with passing through the fantasy as a screen for the desire of the Other. Nawal is situated on the position of the woman as 'not-all' unlike masculinity in Lacanian sexuation. This article shows that her strange acts are love, that is the true ethical acts. Above all her acts are related to the ethics of pure desire beyond the ethics of the Good of Aristotle. In that sense the character of Nawal of 'Incendies' is similar to the one of 'Antigone' as a character in all aspects. In psychoanalysis they all are true subjects that face a void, emptiness in a symbolic structure. They assume underlying impossibility of being/the Symbolic. They don't represent the images of compromise and peace in the normally accepted meaning of the word. A love that they show is not compassion but blind recognition of the excluded, embracing uniqueness of the excluded. This thesis finds resultingly Nawal's acts which can't be understood from viewpoint of feminism practice the ethics of the real, the politics of the real.

Three Dimensional Measurement of Ideal Trajectory of Pedicle Screws of Subaxial Cervical Spine Using the Algorithm Could Be Applied for Robotic Screw Insertion

  • Huh, Jisoon;Hyun, Jae Hwan;Park, Hyeong Geon;Kwak, Ho-Young
    • Journal of Korean Neurosurgical Society
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    • 제62권4호
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    • pp.376-381
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    • 2019
  • Objective : To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine. Methods : Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated. Results : The average transverse angles were $50.60^{\circ}{\pm}6.22^{\circ}$ at C3, $51.42^{\circ}{\pm}7.44^{\circ}$ at C4, $47.79^{\circ}{\pm}7.61^{\circ}$ at C5, and $41.24^{\circ}{\pm}7.76^{\circ}$ at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were $9.72^{\circ}{\pm}6.73^{\circ}$ downward at C3, $5.09^{\circ}{\pm}6.39^{\circ}$ downward at C4, $0.08^{\circ}{\pm}6.06^{\circ}$ downward at C5, and $1.67^{\circ}{\pm}6.06^{\circ}$ upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6. Conclusion : The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.

소모로서의 궁핍: 베케트의 빈궁문학 (Destitution as an Expenditure: Beckett's Literature of Poverty)

  • 박일형
    • 영미문화
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    • 제10권2호
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    • pp.73-97
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    • 2010
  • Representation of destitution may be considered as an expression of a social desire toward forging a bond or solidarity with the impoverished. However, political and ethical demands of the solidarity force the formulaic framework structuring the form of representation to its limits. The thesis aims to examine the responses to such demands within the tradition of modernist literature that can be traced from Charles Baudelaire, Knut Hamsun to Franz Kafka and that somehow culminates with Samuel Beckett, and to analyze how the issue of destitution that weaves through Beckett's works criticizes and inherits such a heritage. Whereas destitution in 19th century Realism is structurally fixed and its potential for change is inherently excluded, for these writers, destitution is no longer the state of rigid reality in which any possibility is limited. It is destitution as an imperative that calls for exploitation of possibilities that can be recuperated from the impoverished condition of destitution. What these writers consistently resist against is destitution that leads to compensation and reward. Since occupying a superior position toward the other as the subject of description or sympathy can be seen as one form of profit or reward, they have persistently pursued absolute solitariness and austere conditions rather than prematurely simulating a sense of solidarity and community. The ultimate goal of destitution as an imperative is to pursue destitution in order to worsen it by identifying and then excluding and expending possessions and assets to a state of penury. This is a paradoxical process that opens up the realm of possibilities of destitution and redefines it as abundance and wealth. Destitution for Beckett as seen in the writers above is the objective of literature. But, what he focuses on is to amplify the shreds of economic world that still remain in a state of poverty and to reveal extreme poverty as a state of odd affluence and to transform it into a pursuit of accumulation and profit. One of his famous axioms, "less is more", contains the essence of such a paradoxical strategy. In a sense, such approach is a twist on the strategy that identifies and uses any remaining potential hidden in destitution as was pursued by other writers. It also expands on the imagination of the destitute described by Hamsun. But Hamsun and Beckett are diametrical opposites. Unlike Hamsun, Beckett does not link imagination with a sense of guilt. Imagination is not intended to overcome the destitute reality nor to culminate in artistic martyrdom as in the case of Kafka's hunger artist. The imagination of the impoverished in Beckett is simply a hilarious game and not an escape that ends in a sense of guilt. This game formulates a "rhetorical question" or derision at the ironical situation where the pursuit of hunger and art as the disinterestedness has been turned into symbolic capital. It is inherently a fundamental critique at the aestheticization of destitution that has been pursued by Modernism. Beckett's efforts at divulging falsehood inherent in non-profit acts such as charity, donation and hospitality are dissections of social fictions in which aestheticization of destitution remains a part of the whole.