排序方式: 共有29条查询结果,搜索用时 46 毫秒
11.
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
12.
Sukho Yoon Youngboo Moon Tae-Wan Lee Heedon Hwang Euijoon Yoon Young Dong Kim Uk Hyun Lee Donghan Lee Hong-Seung Kim Jeong Yong Lee 《Journal of Electronic Materials》2000,29(5):535-541
We investigated the change in the structural and optical properties of InAs/InP quantum structures during growth interruption
(GI) for various times and under various atmospheres in metalorganic chemical vapor deposition. Under AsH3 + H2 atmosphere, the mass transport for the 2D-to-3D transition was observed during the GI. Photoluminescence peaks from both
quantum dots (QDs) and quantum wells were observed from the premature QD samples. The fully developed QDs showed the two distinct
temperature regimes in the PL peak position, full width at half maximum (FWHM) and wavelength-integrated peak intensity. The
two characteristic activation energies were obtained from the InAs/InP QDs: ∼10 meV for intra-dot excitation and 90 ∼ 110
meV for the excitation out of the dots, respectively. It was also observed that the QD evolution kinetics could be suppressed
in PH3 + H2 and H2 atmospheres. The proper control of GI time and atmosphere might be a useful tool to further improve the properties of QDs. 相似文献
13.
14.
Semi JeongHyunchul Choi Kyoungrae ChaJie Li Jong-oh Park Sukho Park 《Sensors and actuators. A, Physical》2011,171(2):429-435
We propose a new electromagnetic actuation (EMA) system for an intravascular microrobot with steering, locomotion and drilling functions. The EMA system consists of 3 pairs of Helmholtz coil and 1 pair of Maxwell coil. Generally, Helmholtz coils can align a microrobot in a desired direction by generating a uniform magnetic flux. If the uniform magnetic field generated by Helmholtz coils can be rotated, a microrobot with Helmholtz coils can also be rotated. On the other hand, a Maxwell coil, which generates a constant gradient magnetic flux, can supply the propulsion force for the microrobot. A microrobot actuated by the proposed EMA system has a spiral shaped body containing two magnets with different magnetization directions. With the proposed EMA system, the microrobot can move to the target region and perform drilling there by the precessional magnetic field of the Helmholtz coil pairs. The propulsion force for the microrobot is produced by the gradient magnetic field generated by the Maxwell coil pair. The moving velocity and the drilling performance of the microrobot can be increased by the propulsion force of the Maxwell coil pair. Through various tests, the feasibility and enhancement of the microrobot actuated by the proposed EMA system were verified. 相似文献
15.
COMIB(COMposite Icon Browser) is a graphical user interface for retrieval of multimedia databases. It gives users the effect of browsing and navigating multimedia objects simultaneously in a screen using composite icons, that may be thumbnails of the several nested attribute values of those objects. Users can specify these attributes with a mouse while browsing the visualized aggregation hierarchy. Both querying and browsing can be interleaved via query reformulation. We show how these features of COMIB overcome the three drawbacks of the browsing paradigm such as no overview of many objects, the repetitious short-sighted navigation, and the weak presentation of a multimedia object. We also explain the retrieval mechanism algebraically and describe the implementation of COMIB based on this mechanism. 相似文献
16.
Hanil JeongSangbok Woo Sukho Kang Jinwoo Park 《Computers & Industrial Engineering》1997,33(3-4):781-784
The job shop scheduling problem has been a major target for many researchers. Unfortunately, though, most of the past studies assumed that a job consists of only a single part. If we assume that a job consists of a batch as in many real manufacturing environment, then we can obtain an improved schedule. However, then, the size of the scheduling problem would become too large to be solved in practical time limit. So, we proposed an algorithm to get an improved schedule by splitting the original batch into smaller batches, and thereby can meet the due date requirement, and adapt to unexpected dynamic events such as machine failure, rush order and expediting. 相似文献
17.
In this paper, we propose a new operator, histogram-by, which provides a grouping for continuous domains, which partitions records into several groups by given ranges of the target attributes. The histogram-by operator can be represented as histogram-by clause in the SQL statement, and can be easily amenable to query optimization. As the application of the histogram-by operator, we introduce a multi-dimensional histogram query, which returns aggregate values of all ranges specified by the histogram-by clause. To process the query efficiently, we propose effective algorithms using aggregate R-trees. Our experimental results show that our algorithms are reliable in terms of performance over the synthetic and real-world datasets. 相似文献
18.
Go Gwangjun Nguyen Van Du Jin Zhen Park Jong-Oh Park Sukho 《International Journal of Control, Automation and Systems》2018,16(3):1341-1354
International Journal of Control, Automation and Systems - This work proposes the targeted transport of therapeutic agents using a thermo-electromagnetically actuated microrobot. This microrobot is... 相似文献
19.
20.
Adaptive and incremental processing for distance join queries 总被引:1,自引:0,他引:1
Hyoseop Shin Bongki Moon Sukho Lee 《Knowledge and Data Engineering, IEEE Transactions on》2003,15(6):1561-1578
A spatial distance join is a relatively new type of operation introduced for spatial and multimedia database applications. Additional requirements for ranking and stopping cardinality are often combined with the spatial distance join in online query processing or Internet search environments. These requirements pose new challenges as well as opportunities for more efficient processing of spatial distance join queries. In this paper, we first present an efficient k-distance join algorithm that uses spatial indexes such as R-trees. Bidirectional node expansion and plane-sweeping techniques are used for fast pruning of distant pairs, and the plane-sweeping is further optimized by novel strategies for selecting a sweeping axis and direction. Furthermore, we propose adaptive multistage algorithms for k-distance join and incremental distance join operations. Our performance study shows that the proposed adaptive multistage algorithms outperform previous work by up to an order of magnitude for both k-distance, join and incremental distance join queries, under various operational conditions. 相似文献