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Chul-Kee Park, JinWook Kim,
Su Youn Yim,
Ah Reum Lee,
Jung Ho Han,
Chae-Yong Kim,
Sung-Hye Park,
Tae Min Kim,
Se-Hoon Lee,
Seung Hong Choi,
Seung-Ki Kim,
Dong Gyu Kim,
Hee-Won Jung
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ABSTRACT: Pseudoprogression is a major diagnostic dilemma in current treatment protocols for malignant gliomas that involve concurrent chemoradiotherapy. We hypothesized that methylation-specific multiplex ligation probe amplification (MS-MLPA), an assay that permits semiquantitative evaluation of promoter methylation, may be used to diagnose pseudoprogression based on the quantification of the methylation status of the O(6)-methylguanine DNA methyltransferase (MGMT) promoter. We examined the methylation ratio of the MGMT promoter with MS-MLPA in 48 samples from glioblastoma patients. The results were compared with those from methylation-specific polymerase chain reaction (MSP), and protein levels were confirmed by immunohistochemical staining. We then evaluated the correlation between those molecular signatures and clinical outcomes. With regard to radiological progression after chemoradiotherapy, the diagnostic accuracy of the MS-MLPA method was 80% (using a cut-off value of 0.2). These results are better than those obtained with MSP (diagnostic accuracy of 68%). Combining the MS-MLPA and MSP methods resulted in a diagnostic accuracy of 93% for the identification of pseudoprogression among patients to whom these results were coherent. These results demonstrate that MS-MLPA is a useful method to predict radiological progression vs pseudoprogression in glioblastoma patients and that the interpretation of these results in combination with MSP results will provide good practical guidelines for clinical decision making in glioblastoma treatment.
Neuro-Oncology 11/2010; 13(2):195-202. · 5.72 Impact Factor
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ABSTRACT: We propose a novel method to enhance a family of ICP(iterative closest point) algorithms by updating velocity. Even though ICP algorithms play a dominant role in a model based tracking, it is difficult to avoid an accumulated tracking error during a continuous motion. It is because that typical ICP algorithms assumes that each of the point in one scan are measured simultaneously while most of the available rangefinders measure each point sequentially. Hence conventional ICP algorithms are prone to be erroneous under a fast motion and an accumulated error during the motion cannot be ignored in many cases. In our approach, we estimate a velocity of a rangefinder numerically over ICP iterations. As a result, distortion of a scan due to the motion can be compensated using estimated velocity. In addition, outliers are effectively rejected during the iteration of velocity update, which means that more accurate and robust motion is trackable. Also we verify a performance and an accuracy of our method by demonstrating simulation and real-world experiment results.
Robotics and Automation (ICRA), 2010 IEEE International Conference on; 06/2010
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ABSTRACT: A mirror world, which is a virtual space modeling a physical space, attracts enormous interests from VR community recently.
Various applications such as Second Life, Google Earth and Virtual Earth have proven their usefulness and potentialities.
We introduce a novel method to build a mirror world by acquiring environment data represented as a point cloud. Since our
system provides a streaming service of the mirror world while gathering the environment information simultaneously, users
located in an immersive display system can navigate and interact in the mirror world reflecting the physical world of the
present state. Mobile agent which is a mobile robot carrying two laser rangefinder is responsible for exploring the physical
world and creating an environment model. Environment modeling involves position tracking method to merge scattered geometric
data. Optimizing method is also need to reduce space complexity of environment model.
07/2009: pages 445-453;
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Virtual and Mixed Reality, Third International Conference, VMR 2009, Held as Part of HCI International 2009, San Diego, CA, USA, July 19-24, 2009. Proceedings; 01/2009
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Human-Computer Interaction. Novel Interaction Methods and Techniques, 13th International Conference, HCI International 2009, San Diego, CA, USA, July 19-24, 2009, Proceedings, Part II; 01/2009
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ABSTRACT: Recent advanced interface technologies allow the user to interact with different spaces such as virtual reality (VR), augmented reality (AR) and ubiquitous computing (UC) spaces. Previously, human computer interaction (HCI) issues in VR, AR and UC have been largely carried out in separate communities. Here, we combine these three interaction spaces into a single interaction space, called tangible space. We propose the VARU framework which is designed for rapid prototyping of a tangible space application. It is designed to provide extensibility, flexibility and scalability. Depending on the available resources, the user could interact with either the virtual, physical or mixed environment. By having the VR, AR and UC spaces in a single platform, it gives us the possibility to explore different types of collaboration across the different spaces. As a result, we present our prototype application which is built using the VARU framework.
Virtual Reality Conference, 2008. VR '08. IEEE; 04/2008
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IEEE Virtual Reality Conference 2008 (VR 2008), 8-12 March 2008, Reno, Nevada, USA, Proceedings; 01/2008
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Proceedings of the International Conference on Advances in Computer Entertainment Technology, ACE 2008, Yokohama, Japan, December 3-5, 2008; 01/2008
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ABSTRACT: This paper presents a human-machine interface for tele-operated construction robot systems. By using augmented reality techniques, we developed an immersive interface for tele-operated construction robot system. Compared to the traditional interface using a monitor view only, the developed AR interface system allows the operator to see the invisible image out of camera view by using a virtual 3D model. Also, this AR system notifies the operator of a danger area and gives the operator a guide for completion of task by using the augmented reality. For these reasons, the operator can rapidly and accurately recognize depth information of structure in construction site. Therefore, the operator can easily and safely complete construction operation. Also, the efficiency of construction operation can be improved and the construction period can be decreased.
Control, Automation and Systems, 2007. ICCAS '07. International Conference on; 11/2007
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ABSTRACT: This paper describes the design, construction, and performance
analysis of the Eclipse, a redundantly actuated six-degree-of-freedom
parallel mechanism intended for rapid machining. The Eclipse is a
compact mechanism capable of performing five-face machining in a single
setup while retaining the advantages of high stiffness and high accuracy
characteristic of parallel mechanisms. We compare numerical and
algebraic algorithms for the forward and inverse kinematics of a class
of the Eclipse and formalize the notion of machine tool workspace. We
also develop a simple method for the first-order elasto-kinematic
analysis of parallel mechanisms that is amenable to design iterations. A
complete characterization of the singularities of the Eclipse is given,
and redundant actuation is proposed as a solution. The Eclipse case
study demonstrates how diverse analytical tools originally developed in
a robotics context can be synthesized into a practical design
methodology for parallel mechanisms
IEEE Transactions on Robotics and Automation 09/2001;
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IEEE Transactions on Robotics. 01/2001; 17:423-434.
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ABSTRACT: This paper addresses the kinematic sensitivity of the three degree-of-freedom 3-UPU parallel mechanism, a mechanism consisting of a fixed base and a moving platform connected by three serial UPU chains. Although a mathematical mobility analysis confirms that the mechanism has three degrees of freedom, hardware prototypes exhibit unexpected large motions of the platform even when the three prismatic joints are locked at arbitrary configurations. Existing mathematical classifications of kinematic singularities also fail to explain the gross motions of the 3-UPU. This paper resolves this apparent paradox. We show that the 3-UPU is highly sensitive to certain minute clearances in the universal joint, and that a careful kinematic sensitivity analysis of the 3-UPU augmented with virtual joints satisfactorily explains the gross motions. Observations with a hardware experimental prototype confirm the results of our sensitivity analysis.
Mechanism and Machine Theory.
