• Title/Summary/Keyword: Time and Motion Studies

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Stochastic finite element based seismic analysis of framed structures with open-storey

  • Manjuprasad, M.;Gopalakrishnan, S.;Rao, K. Balaji
    • Structural Engineering and Mechanics
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    • v.15 no.4
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    • pp.381-394
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    • 2003
  • While constructing multistorey buildings with reinforced concrete framed structures it is a common practice to provide parking space for vehicles at the ground floor level. This floor will generally consist of open frames without any infilled walls and is called an open-storey. From a post disaster damage survey carried out, it was noticed that during the January 26, 2001 Bhuj (Gujarat, India) earthquake, a large number of reinforced concrete framed buildings with open-storey at ground floor level, suffered extensive damage and in some cases catastrophic collapse. This has brought into sharp focus the need to carry out systematic studies on the seismic vulnerability of such buildings. Determination of vulnerability requires realistic structural response estimations taking into account the stochasticity in the loading and the system parameters. The stochastic finite element method can be effectively used to model the random fields while carrying out such studies. This paper presents the details of stochastic finite element analysis of a five-storey three-bay reinforced concrete framed structure with open-storey subjected to standard seismic excitation. In the present study, only the stochasticity in the system parameters is considered. The stochastic finite element method used for carrying out the analysis is based on perturbation technique. Each random field representing the stochastic geometry/material property is discretised into correlated random variables using spatial averaging technique. The uncertainties in geometry and material properties are modelled using the first two moments of the corresponding parameters. In evaluating the stochastic response, the cross-sectional area and Young' modulus are considered as independent random fields. To study the influence of correlation length of random fields, different correlation lengths are considered for random field discretisation. The spatial expectations and covariances for displacement response at any time instant are obtained as the output. The effect of open-storey is modelled by suitably considering the stiffness of infilled walls in the upper storey using cross bracing. In order to account for changes in soil conditions during strong motion earthquakes, both fixed and hinged supports are considered. The results of the stochastic finite element based seismic analysis of reinforced concrete framed structures reported in this paper demonstrate the importance of considering the effect of open-storey with appropriate support conditions to estimate the realistic response of buildings subjected to earthquakes.

A Fundamental Study of VIV Fatigue Analysis Procedure for Dynamic Power Cables Subjected to Severely Sheared Currents (강한 전단 해류 환경에서 동적 전력케이블의 VIV 피로해석 절차에 관한 기초 연구)

  • Chunsik Shim;Min Suk Kim;Chulmin Kim;Yuho Rho;Jeabok Lee;Kwangsu Chea;Kangho Kim;Daseul Jeong
    • Journal of the Society of Naval Architects of Korea
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    • v.60 no.5
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    • pp.375-387
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    • 2023
  • The subsea power cables are increasingly important for harvesting renewable energies as we develop offshore wind farms located at a long distance from shore. Particularly, the continuous flexural motion of inter-array dynamic power cable of floating offshore wind turbine causes tremendous fatigue damages on the cable. As the subsea power cable consists of the helical structures with various components unlike a mooring line and a steel pipe riser, the fatigue analysis of the cables should be performed using special procedures that consider stick/slip phenomenon. This phenomenon occurs between inner helically wound components when they are tensioned or compressed by environmental loads and the floater motions. In particular, Vortex-induced vibration (VIV) can be generated by currents and have significant impacts on the fatigue life of the cable. In this study, the procedure for VIV fatigue analysis of the dynamic power cable has been established. Additionally, the respective roles of programs employed and required inputs and outputs are explained in detail. Demonstrations of case studies are provided under severely sheared currents to investigate the influences on amplitude variations of dynamic power cables caused by the excitation of high mode numbers. Finally, sensitivity studies have been performed to compare dynamic cable design parameters, specifically, structural damping ratio, higher order harmonics, and lift coefficients tables. In the future, one of the fundamental assumptions to assess the VIV response will be examined in detail, namely a narrow-banded Gaussian process derived from the VIV amplitudes. Although this approach is consistent with current industry standards, the level of consistency and the potential errors between the Gaussian process and the fatigue damage generated from deterministic time-domain results are to be confirmed to verify VIV fatigue analysis procedure for slender marine structures.

A Study on Channel 4's Station Identification: focused on 'Modular Typography'

  • John, Adjah;Hong, Mi-Hee
    • Cartoon and Animation Studies
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    • s.42
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    • pp.241-262
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    • 2016
  • British TV Channel 4 is one of the famous TV Channel in the world. Its station ID has also played a leading role in the developments of Motion Graphics including station IDs. This station ID's main visual design concept is its name and an iconic logo '4' at the same time. The first channel 4 station ID was designed by using modular typography to construct the iconic '4'. Modular typography is a technique of creating letters with similar elements. Channel 4's station ID was constructed from coloured polygons. The polygons split and converge at the same point in 3D space. Modularity in Channel 4's station ID is evidenced by the similar units of polygons. After the first station ID, Channel 4 was re-branded. Eventhough the station IDs which followed did not use coloured and geometrical polygons, modularity is seen in most of the station IDs especially between 2004 - 2011. In these station IDs, the iconic '4' is formed from similar natural and environmental objects like rocks, buildings, lights etc. In this analysis paper, there is a visual narrative on the history of Channel 4, the concept of modular typography in the original station ID and the application of modular typography in other Channel 4's station IDs.

An FSI Simulation of the Metal Panel Deflection in a Shock Tube Using Illinois Rocstar Simulation Suite (일리노이 록스타 해석환경을 활용한 충격파관 내 금속패널 변형의 유체·구조 연성 해석)

  • Shin, Jung Hun;Sa, Jeong Hwan;Kim, Han Gi;Cho, Keum Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.5
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    • pp.361-366
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    • 2017
  • As the recent development of computing architecture and application software technology, real world simulation, which is the ultimate destination of computer simulation, is emerging as a practical issue in several research sectors. In this paper, metal plate motion in a square shock tube for small time interval was calculated using a supercomputing-based fluid-structure-combustion multi-physics simulation tool called Illinois Rocstar, developed in a US national R amp; D program at the University of Illinois. Afterwards, the simulation results were compared with those from experiments. The coupled solvers for unsteady compressible fluid dynamics and for structural analysis were based on the finite volume structured grid system and the large deformation linear elastic model, respectively. In addition, a strong correlation between calculation and experiment was shown, probably because of the predictor-corrector time-integration scheme framework. In the future, additional validation studies and code improvements for higher accuracy will be conducted to obtain a reliable open-source software research tool.

Recognition and Enforcement of Foreign Arbitral Awards in Korea (한국에서의 외국중재판정의 승인과 집행)

  • Kim, Sang-Ho
    • Journal of Arbitration Studies
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    • v.17 no.3
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    • pp.3-30
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    • 2007
  • The New York Convention(formally called "United Nations Convention on the Recognition and Enforcement of Foreign Arbitral Awards") done in New York on June 10, 1958 has been adhered to by more than 140 States at the time of this writing, including almost all important trading nations from the Capitalist and Socialist World as well as many developing countries. The Convention can be considered as the most important Convention in the field of arbitration and as the cornerstone of current international commercial arbitration. Korea has acceded to the New York Convention since 1973. When acceding to the Convention, Korea declared that it will apply the Convention to the recognition and enforcement of awards made only in the territory of another Contracting State on the basis of reciprocity. Also, Korea declared that it will apply the Convention only to differences arising out of legal relationships, whether contractual or not, which are considered as commercial under the national law of Korea. The provisions relating to the enforcement of arbitral awards falling under the New York Convention begin at Article III. The Article III contains the general obligation for the Contracting States to recognize Convention awards as binding and to enforce them in accordance with their rules of procedure. The Convention requires a minimum of conditions to be fulfilled by the party seeking enforcement. According to Article IV(1), that party has only to supply (1) the duly authenticated original award or a duly certified copy thereof, and (2) the original arbitration agreement or a duly certified copy thereof. In fulfilling these conditions, the party seeking enforcement produces prima facie evidence entitling it to obtain enforcement of the award. It is then up to the other party to prove that enforcement should not be granted on the basis of the grounds for refusal of enforcement enumerated in the subsequent Article V(1). Grounds for refusal of enforcement are stipulated in Article V is divided into two parts. Firstly, listed in the first Para. of Article V are the grounds for refusal of enforcement which are to be asserted and proven by the respondent. Secondly, listed in Para. 2 of Article V, are the grounds on which a court may refuse enforcement on its own motion. These grounds are non-arbitrability of the subject matter and violation of the public policy of the enforcement country. The three main features of the grounds for refusal of enforcement of an award under Article V, which are almost unanimously affirmed by the courts, are the following. Firstly, The grounds for refusal of enforcement mentioned in Article V are exhaustive. No other grounds can be invoked. Secondly, and this feature follows from the first one, the court before which enforcement of the award is sought may not review the merits of the award because a mistake in fact or law by the arbitrators is not included in the list of grounds for refusal of enforcement set forth in Article V. Thirdly, the party against whom enforcement is sought has the burden of proving the existence of one or more of the grounds for refusal of enforcement. The grounds for refusal of enforcement by a court on its own motion, listed in the second Para. of Article V, are non-arbitrability of the subject matter and public policy of the enforcement country. From the court decisions reported so far at home and abroad, it appears that courts accept a violation of public policy in extreme cases only, and frequently justify their decision by distinguishing between domestic and international public policy. The Dec. 31, 1999 amendment to the Arbitration Act of Korea admits the basis for enforcement of foreign arbitral awards rendered under the New York Convention. In Korea, a holder of a foreign arbitral award is obliged to request from the court a judgment ordering enforcement of the award.

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A Study on Expressing 3D Animation by Visual Direction : focused on 〈 How to train your dragon 〉 (시각적 연출에 의한 3D 입체 애니메이션 표현 연구: 〈드래곤 길들이기〉를 중심으로)

  • Kim, Jung-Hyun
    • Cartoon and Animation Studies
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    • s.26
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    • pp.1-30
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    • 2012
  • The purpose of animation is to give interesting stories to an audience through motion. To achieve the purpose, over the past century since its inception, animation has adopted many kinds of technologies, and thus developed diverse narrative methods and visual expression techniques. In addition, with the advancement of expression techniques, all elements making up animation have gradually been systemized, and at the same time, have helped express the worlds beyond the reality. As a result, people have faced the era when an audience can watch everything imaginated by an animation director on a big screen. These days, more efforts have been made in order for the audience to feel much more than enjoy pictures moving in a frame. In other words, the purpose of the animation is changing from the passive viewing of animation to feeling and sensing stuffs through the animation. In the center of the changing process is 3D technology which gives new interesting to an audience. Sometime ago, a 3D animation movie was produced in Korea. But it did not bring out box-office profits, for it failed to give satisfaction to an audience who expected high perfection and beauty being able to be rivalled to those of international 3D animation movies. The failure is attributable to the fact that the domestic 3D animation production industry is merely in the early stage, and has not sufficient human resources, technology, and experiences in producing 3D animation films. Moreover, the problem is that most studies on 3D focus on the technologies related to reenactment, but that few studies on the images, which an audience directly faces, have been conducted. Under the domestic circumstance, the study on stereoscopic image screen of , a 3D stereoscopic animation film which was released in 2010 and has been seen as the best successful 3D stereoscopic animation, is worthwhile. Thus this thesis conducted theoretical consideration and case analysis focusing on the visual direction that creates the pictures to deliver abundant three dimensional effect so that it can be used as a basic data when producing high quality-domestic 3D animation and training professional labor forces. In the result, it was found that the 3D animation was not a new area, but the area which has been expanded and changed by applying the characteristics of 3D image based on the principles of the existing media aesthetics. This study might be helpful to establish the foundation of the theoretical studies necessary for producing 3D animation contents for realizing the sense of reality.

Studies on the mechanism in the induced to unfertilized eggs(male sterility of Silkworm) by protected environment during pupae period (용기의 보호환경에 따른 불수정란(웅성불임잠)의 유발기구에 관한 조사연구)

  • 윤종관;오준식
    • Journal of Sericultural and Entomological Science
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    • v.15 no.2
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    • pp.9-14
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    • 1973
  • In order to find out effects of the generative power of silk worm moth which have been brought up in the high temperature accommodation at their pupa stage. For this specific study, 9 different kinds of male silk worms have been selected as specimen. All those specimen were brought up in the normal temperature at their larvae stage and after the pupation period they have been accommodated in the condition of high temperature for a certain length in accordance with the study programme. Afterwards, those mlae specimen were copulated with Suwon jam 103${\times}$104 which were all brought up in normal conditions. This study was carried out to find the copulation function as well as the ratio of unfertilized eggs(male sterility test). Results of study have been revealed as follows: 1) Although some differences were observed, male pura which have been brought up in the condition of high temperature shown the low rate of unfertilized eggs rather than those were brought up in the normal conpition. 2) In this group the eclosion(emergency) has been found to be poor rather, than those specimen brought up in normal conditions. 3) The copulation function of Moran, Daedong, J124 and C108 specimen were found to be poor than those of Suwon jam. 4) Fertility rate of Moran, Daedong, J124 and C108 was found to be around 65%. This figure is rather lower than what we normally expect. 5) Unfertilized egg ratio of Moran, Daedong and C108 were found to be around 20% if they were brought up in the condition of high temperature for one day from the time of pupation: 40% at 2 days, and 70% at 3 days duration. More than 3 days treatment has shown no progress in the unfertilized egg ratio. 6) One day's treatment for the pupa at the later stage has shown the unfertilized egg ratio of about 10%; 20% at 2 day's treatment, 35% at 3 day's treatment, 40-60% at 4 day's treatment, more than 60% at 5 day's treatment, and the 70% of fertilized egg ratio was only observed when the treatment days come to 7 days. It was understood that the unfertilized egg ratio was high at the antepupa stage rather than that of post-pupa stage. 7) According to the result of observation the sperm in copulatory pouch and seminal receptacle out of the normal female silk worm which have been copulated with the male brought up in the condition of high temperature at their moth stage. The reproduction system found in the control zone has been found to be normal and the sperm is amountful and active in motion while the sperm found in the treatment to be limited in amount and slow in motion. The observation was made within 5 hours from the copulation. 8) According to the result of observation of sperm of seminal receptacles of the female silkworm moth, and according to that observation of sperm in the seminal receptacle in female silkworm moth, the amount of sperm and mobility in the female moth brought up in high temperature were poor comparing that were brought up in normal temperature zone. Some of them are even found to be no trace of such. 9) Appearance and mosle of the copulatory organ of the male silkworm moth was found to be no anatomical change. 10) Testis of the later pupa stage which was brought up in the high temperature was found to be almost net developed to anucleate sperm and they are degenerated at stage of between maturation division and sperm abnormal stage. Mean time at control zone, the formation of anucleate sperm was already observed.

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Wedge-Shaped Resection for Massive Xanthomatosis of Achilles Tendon (양측 아킬레스건에 발생한 거대 황색종의 쐐기형 절제술을 이용한 수술적 치료)

  • Kim, Sungmin;Ahn, Yeong Seub;Jung, Dong-Min;Jung, Sung Taek
    • Journal of the Korean Orthopaedic Association
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    • v.56 no.2
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    • pp.157-163
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    • 2021
  • Purpose: Xanthomatosis of the Achilles tendons is rare. In some patients, however, the lesions in the Achilles tendon need to be removed, which may be painful and disfiguring. While studies of successful surgical outcomes for the total resection and reconstruction of the Achilles tendon have been reported, reconstruction surgery has a technical challenge, and extended surgical exposures are required. This study analyzed five cases of bilateral xanthoma of the Achilles tendon, which was treated surgically using a wedge-shaped tendon-sparing approach to eliminate the need for tendon reconstruction. Materials and Methods: From July 2010 to May 2018, five patients with xanthomatosis in both Achilles tendons underwent wedge-shaped tendon preserving surgery. The average age was 49 years (range, 40-55 years), and the follow-up period was 21.4 months (range, 12-31 months). The patients consisted of three males and two females. Complications related to surgery were recorded. The outcome measures included the range of motion of the ankle joint, American Orthopaedic Foot and ankle Society (AOFAS) ankle/hindfoot score, and visual analogue scale (VAS) for overall satisfaction at the last follow-up. The availability of a single-limb heel raise and returning time to work were also measured. Results: Wound dehiscence that did not require secondary surgery was noted in one patient. At the last follow-up, the range of motion of the ankle joint was normal in all patients. The mean AOFAS ankle/hindfoot score was 91 (range, 85-96) and the VAS for the overall satisfaction ranged from 8 to 10. The average time between surgery and return to work was 27.6 days (range, 17-58 days) and all patients could perform a single-limb heel raise test. Conclusion: The tendon-sparing technique, which can preserve the anatomical functioning of the Achilles tendon, could be an excellent surgical approach because it has very promising functional and cosmetic surgical outcomes in patients with Achilles tendon xanthomatosis.

The Evaluation of Usefulness of Pixelated Breast-Specific Gamma Imaging in Thyroid scan (Pixelated Breast-Specific Gamma Imaging(BSGI) 감마 카메라를 이용한 갑상선 검사의 유용성 평가)

  • Jung, Eun-Mi;Seong, Ji-Hye;Yoo, Hee-Jae
    • The Korean Journal of Nuclear Medicine Technology
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    • v.15 no.1
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    • pp.90-93
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    • 2011
  • Purpose: A Pixelated BSGI gamma camera has features to enhance resolution and sensitivity and minimize the distance between detector and organs by narrow FOV. Therefore, it is known as useful device to examine small organs such as thyroid, parathyroid and gall bladder. In general, when we would like to enlarge the size of images and obtain high resolution images by gamma camera in nuclear medicine study, we use pinhole collimator. The purpose of this study is to evaluate the usefulness of Pixelated BSGI gamma camera and to compare to it using pinhole collimator in thyroid scan which is a study of typical small organs. Materials and methods: (1) The evaluation of sensitivity and spatial resolution: We measured sensitivity and spatial resolution of Pixelated BSGI with LEHR collimator and Infinia gamma camera with pinhole collimator. The sensitivity was measured by point source sensitivity test recommended by IAEA. We acquired images considering dead time in BSGI gamma camera for 100 seconds and used $^{99m}TcO4-\;400{\mu}Ci$ line source. (2) The evaluation of thyroid phantom: The thyroid phantom was filled with $^{99m}TcO4-$. After set 300 sec or 100 kcts stop conditions, we acquired images from both pixelated BSGI gamma camera and Infinia gamma camera with LEHR collimator. And we performed all thyroid studies in the same way as current AMC's procedure. Results: (1) the result of sensitivity: As a result, the sensitivity and spatial resolution of pixelated BSGI gamma camera were better than Infinia's. The sensitivities of pixelated BSGI and Infinia gamma camera were $290cps/{\mu}Ci$ and $350cps/{\mu}Ci$ respectively. So, the sensitivity of pixelated BSGI was 1.2 times higher than Infinia's (2) the result of thyroid phantom: Consequently, we confirmed that images of Pixelated BSGI gamma camera were more distinguishable between hot and cold spot compared with Infinia gamma camera. Conclusion: A pixelated BSGI gamma camera is able to shorten the acquisition time. Furthermore, the patients are exposed to radiation less than before by reducing amount of radiopharmaceutical doses. Shortening scan time makes images better by minimizing patient's breath and motion. And also, the distance between organ and detector is minimized because detector of pixelated BSGI gamma camera is small and possible to rotate. When patient cannot move at all, it is useful since device is feasible to move itself. However, although a pixelated BSGI gamma camera has these advantages, the effect of dead time occurs over 2000 cts/s since it was produced only for breast scan. So, there were low concentrations in organ. Therefore, we should consider that it needs to take tests to adjust acquisition time and amount of radiopharmaceutical doses in thyroid scan case with a pixelated BSGI gamma camera.

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Impact of Hemodialysis on Left Ventricular Performance: A Doppler Echocardiographic Study (혈액투석 유지요법 환자에서 투석 전후의 좌심실 Doppler 심초음파를 이용한 기능지표의 변화)

  • Kang, Dong-Oh;Lee, Du-Ha;Kim, Hyun-Seo;Kim, Hyun-Su;Kim, Sung-Rok;Park, Jong-Seon
    • Journal of Yeungnam Medical Science
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    • v.16 no.2
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    • pp.309-317
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    • 1999
  • Background: Left ventricular diastolic filling is an important determinant for maintenance of cardiac output during hemodialysis. Few investigators have studied the influence of hemodialysis on diastolic function. To evaluate the change of left ventricular systolic and diastolic function. we performed M-mode and Doppler echocardiographic studies before and after hemodialysis. Methods: The study population consisted of 30 patients(15 patients were male, mean age $45{\pm}10$ years) with CRF on maintenance hemodialysis. They have normal left ventricular systolic function(Fractional shortening>30%) and no evidence of valvular heart disease or regional wall motion abnormalities. The ejection fraction (EF) was measured using M-mode echocardiography and Doppler indices such as peak E velocity, peak A velocity, isovolumetric relaxation time(IVRT), deceleration time(DT). and left ventricular ejection time(LVET) obtained from Doppler echocardiography. The index of myocardial performance (IMP) was calculated from each of the Doppler velocity indices. Results: The weight reduction after hemodialysis was $2.1{\pm}1.0kg$(p<0.0001), After hemodialysis, there was some decrease in blood pressure(p<0.05), but no significant change in heart rate, EF and fractional shortening, mean VCF, peak A velocity, and DT. And significant reduction in peak E velocity, E/A ratio(p<0.0001. p<0.001), and significant increase in IVRT and IMP(p<0.05, p<0.0001) were noted. Conclusion: In conclusion, preload reduction is the main mechanism that accounts for changes in Doppler diastolic indices after hemodialysis. And an increased IMP suggests that diastolic function may be aggravated after hemodialysis, and that implies impaired left ventricular filling and disturbed left ventricular compliance.

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