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1.
Kwon J Park S Park J Kim B 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2007,221(4):397-405
Recently, the capsule endoscope has been highlighted for the patient's convenience and the possibility of application in the small intestine. However, the capsule endoscope has some limitations in obtaining an image of the digestive organ because its movement depends only on the peristaltic motion. In order to solve these problems, it is necessary to determine the locomotive mechanism of the capsule endoscope. Therefore, the present authors have already proposed an earthworm-like robot, which has a locomotive mechanism. However, this mechanism should be designed so that the earthworm-like robot has a larger stroke than the critical stroke required to perform motion inside the small intestine. In this study, therefore, not only is the modelling of the locomotive process based on a biomechanical study presented but also the movement of the earthworm-like robot in the small intestine is simulated. Through the simulation process, the variation in the critical stroke with regard to the elastic modulus of the mesentery is investigated. Finally, from an in vitro test of the proposed robot, it is found that the experimental result is very similar to that of the simulation. Consequently, the present work will provide guidelines for designing an earthworm-like robot for diagnosis of the small intestine. 相似文献
2.
Abstract: This article developed a generalized model incorporating three stochastic input variables in the Highway Capacity Manual (HCM) delay equation and analyzed the delay variability explicitly considering variations in key input variables including traffic volume, effective green time, and saturation flow rate. An integration method was used for calculations of mean and variance of the HCM delay. Unlike the previous Expectation Function Method, the proposed integration method can be applied for both undersaturated and oversaturated situations. The applicability of the proposed methodology was demonstrated through a hypothetical case study for a lane group at an isolated signalized intersection. The effects of stochastic variables (e.g., traffic volume, saturation flow rate, and effective green time) and correlations among these variables in the HCM delay were examined. 相似文献
3.
Park J Ryu J Choi SK Seo E Cha JM Ryu S Kim J Kim B Lee SH 《Analytical chemistry》2005,77(20):6571-6580
We present a microfabricated hybrid biopolymer microcantilever, in which the contractile force of self-organized cardiomyocytes can be measured and studied, as a prototype for the development of cell-driven actuators. The microcantilever is made of a flexible, transparent, biocompatible poly(dimethylsiloxane) substrate, using a simple microfabrication technique. Seeding and culturing cardiomyocytes on the specific cantilever allows us to perform highly sensitive, quantitative, and noninvasive measurement of the contractile force of the self-organized cells in real time. The motions of the microcantilever showed good agreement with an analytical solution based on Stoney's equation and finite element modeling (FEM) of the hybrid system. Immunostaining of the cells on the hybrid system showed continuous high-order coalignment of actin filaments and parallel sarcomeric organization in the direction of the longitudinal axis of the microcantilever without structural constraints, such as microgrooves or lines, and proved our FEM and the synchronous contraction of cardiomyocytes. The presented device should facilitate measurement of the contractile force of self-organized cardiomyocytes on a specific area, which may help the understanding of heart failure and the design of optimal hybrid biopolymer actuators, as well as assist development of a microscale cell-driven motor system. 相似文献
4.
Baek Hyun Kim Jong Hoon Park Byungkyu Kim Do-Kyun Kwon 《Metals and Materials International》2012,18(6):1067-1072
Liquid phase sintering of lead zirconate titanate (abbreviated as PZT) ceramics with a 0.78 PbO-0.22 CuO (10:1 in weight ratio) flux was investigated. A small amount sintering flux consisting of a stoichiometrically mixed oxide of PbO-CuO with a eutectic composition successfully accelerated densification of the PZT ceramics far below the conventional sintering temperature. With the 3 wt% flux additions, full densifications of the PZT ceramics were achieved at temperatures as low as 825 °C. The results obtained in the crystal structure, microstructure, and electrical property analyses suggest that the Cu2+ impurity ion substitutes as an acceptor center for the perovskite B-site without forming isolated secondary phases. Defect associates of the Cu2+ impurities and charge compensating oxygen vacancies appear to affect dielectric and piezoelectric properties of the sintered PZT samples in both positive and negative ways by forming defect dipoles. When the Cu2+ content is small, slightly improved dielectric and piezoelectric performances were achieved, though ferroelectric relaxation was obviously developed at the higher Cu2+ contents. For the PZT samples sintered at 825 °C with 3 wt% flux addition, relative dielectric permittivity was 2200 and dielectric loss was less than 2%. Remnant polarization, coercive fields, and piezoelectric coefficient (d33) were 32 μC/cm2, 8.9 kV/cm and 373 pC/N, respectively. 相似文献
5.
Joonhyo Kim Byungkyu Park Joyoung Lee Jongsun Won 《Engineering Applications of Artificial Intelligence》2011,24(2):318-324
Travel time is the most intuitive measure of effectiveness for road users and transportation agency operators. However, travel times derived from speed data measured at fixed point sensors often varies from actual travel time. This is, in part, due to the intentional positioning of sensors to avoid lane changing and/or to inadequate numbers of sensors capturing the dynamic characteristics inherent in freeway traffic flow. This paper presents an approach that optimizes the location of sensors in a freeway to support more accurate estimations of travel times than those obtained from conventionally deployed fixed point sensors. Evaluation results, under varying traffic conditions, including incidents, showed that the proposed approach produced average travel time estimation errors within 10% and performed much better than the conventional approach. Thus, the proposed approach provides a promising tool to support re-positioning of the existing non-intrusive point sensors (e.g., video sensors) or deployment of new sets of point sensors for improving travel time estimation. 相似文献
6.
Sukho Park Seokkyu Ryu Seokchang Ryu Deokho Kim Byungkyu Kim 《Journal of Mechanical Science and Technology》2006,20(5):668-674
In order to develop a cell based robot, we present a micro-mechanical force measurement system for the biological muscle actuators,
which utilize glucose as a power source. The proposed measurement system is composed of a micro-manipulator, a force transducer
with a glass probe, a signal processor, an inverted microscope and video recording system. Using this measurement system,
the contractile force and frequency of the cardiac myocytes were measured in real time and the magnitudes of the contractile
force of each cardiac myocyte under different conditions were compared. From the quantitative experimental results, we could
estimate that the force of cardiac myocytes is about 20–40 μN, and show that there are differences between the control cells
and the micro-patterned cells. 相似文献
7.
Jaewook Ryu Senghwan Jung Seung-Ki Lee Byungkyu Kim 《Journal of Mechanical Science and Technology》2005,19(10):1910-1918
Characterizing electrochemical polymerization of polypyrrole film on a substrate depends on many parameters. Among them, potential
difference and cumulative charges play important role. The level of potential difference affects the quality of the polypyrrole.
On the contrary, cumulative charge affects the thickness of the polypyrrole. The substrate surface is adjusted physically
and chemically by treating with sandblasting and the addition of thiol for surface adhesion improvement. Experimental results
show that the sandblasted and thiol treated substrate provides better adhesion than non-sandblasted and non-thiol treated
substrate. 相似文献
8.
Deok-Ho?Kim Byungkyu?KimEmail author Jong-Oh?Park 《Journal of Mechanical Science and Technology》2004,18(5):789-797
The nanoscale sensing and manipulation have become a challenging issue in micro/nanorobotic applications. In particular, a
feedback sensor-based manipulation is necessary for realizing an efficient and reliable handling of particles under uncertain
environment in a micro/ nano scale. This paper presents a piezoresistive MEMS cantilever for nanoscale force measurement in
microrobotics. A piezoresistive MEMS cantilever enables sensing of gripping and contact forces in nanonewton resolution by
measuring changes in the stress-induced electrical resistances. The calibration of a piezoresistive MEMS cantilever is experimentally
carried out. In addition, as part of the work on nanomanipulation with a piezoresistive MEMS cantilever, the analysis on the
interaction forces between a tip and a material, and the associated manipulation strategies are investigated. Experiments
and simulations show that a piezoresistive MEMS cantilever integrated into a microrobotic system can be effectively used in
nanoscale force measurements and a sensor-based manipulation. 相似文献
9.
Sukho Park Hyunjun Park Sungjin Park Byungkyu Kim 《Journal of Mechanical Science and Technology》2006,20(7):1012-1018
Diagnosis and treatment using the conventional flexible endoscope in gastro-intestinal tract are very common since advanced
and instrumented endoscopes allow diagnosis and treatment by introducing the human body through natural orifices. However,
the operation of endoscope is very labor intensive work and gives patients some pains. As an alternative, therefore, the capsule
endoscope is developed for the diagnosis of digestive organs. Although the capsule endoscope has conveniences for diagnosis,
it is passively moved by the peristaltic waves of gastro-intestinal tract and thus has some limitations for doctor to get
the image of the organ and to diagnose more thoroughly. As a solution of these problems, various locomotive mechanisms for
capsule endoscopes are introduced. In our proposed mechanism, the capsule-type microrobot has synchronized multiple legs that
are actuated by a linear actuator and two mobile cylinders inside of the capsule. For the feasibility test of the proposed
microrobot, a series of in-vitro experiments using small intestine without incision were carried out. From the experimental
results, our proposed microrobot can advance along the 3D curved and sloped path with the velocity of about 3.29–6.26 mm/sec
and 35.1–66.7% of theoretical velocity. Finally, the proposed locomotive mechanism can be not only applicable to micro capsule
endoscopes but also effective to advance inside of gastro-intestinal tract. 相似文献
10.
Jungyul Park Sangmin Kim Deok-Ho Kim Byungkyu Kim Sang Joo Kwon Jong-Oh Park Kyo-Il Lee 《Mechatronics, IEEE/ASME Transactions on》2005,10(5):601-606
This paper presents the design and control of a sensorized microgripper using a voice coil motor and a flexure mechanism. To increase the gripping sensitivity, shape design and determination of sensor attachment position are performed using finite element analysis. Empirical models of the microgripper are acquired for the design of position control and gripping force control. By using the identified models, both the perfect tracking controller for position control and the adaptive zero-phase error tracking controller for force control are implemented. The effectiveness of the proposed model-based control methods is verified by experimental studies. 相似文献