• Title/Summary/Keyword: adaptive changes

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DSP Implementation of QPSK Signal Generator for Underwater Supersonic Waves Communication (수중 초음파 통신을 위한 QPSK 신호발생기의 DSP 구현에 관한 연구)

  • Lee, Deok-Hwan;Ji, Yong-Il;Kim, Seung-Geun;Lim, Yong-Gon;Ko, Hak-Lim
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.341-344
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    • 2003
  • There communicates using tire supersonic waves in tire underwater, that is different from tire ground that use tire propagation. Because using Law frequency to come under tire waves, bandwidth that is able to communicate is very smaller that tire mobile communication of tire ground. Also, The channel environment changes rapidly in tire shallow underwater than tire ground. Due to such a reason, data transmission technic that is able to tire maximum application to restricted bandwidth and tire signal processing technics that is able to conquer tire rapid changes of tire channel environment are being used. Algorithm is used at tire application of these technic has a lot of tire calculating quantity. So this research reveals small bulk and equal performance using one DSP chip and then implements QPSK transmitter, that uses SHARC DSP of Analog Device company, for tire underwater supersonic waves communication rapidly decrease tire calculating quantity.

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Adaptive Multipath Routing Algorithm for Low-power Lossy Networks (저전력 손실 네트워크에서의 적응형 다중경로 라우팅 알고리즘)

  • Kim, Seunghyun;Joung, Jinoo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.2
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    • pp.91-96
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    • 2019
  • For a wireless sensor network in general, efficient routing decision is important because wireless connections are not stable, sensitive to external interference, and topology changes dynamically. RPL standard of IETF is not flexible to various environmental changes and causes packet loss and delay due to topological imbalance. Sending packets through multipath can partially remedy this problem. The multipath routing, however, can introduce significant delay overhead by allocating unnecessary timeslots. This paper proposes an RPL using multipath adaptively according to network conditions. We show by simulations that the proposed algorithm is more efficient than the basic RPL and the multipath RPL.

Autophagy and Digestive Disorders: Advances in Understanding and Therapeutic Approaches

  • Thein, Wynn;Po, Wah Wah;Choi, Won Seok;Sohn, Uy Dong
    • Biomolecules & Therapeutics
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    • v.29 no.4
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    • pp.353-364
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    • 2021
  • The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.

Position Control of Shape Memory Alloy Actuators Using Self Tuning Fuzzy PID Controller

  • Ahn Kyoung-Kwan;Nguyen Bao Kha
    • International Journal of Control, Automation, and Systems
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    • v.4 no.6
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    • pp.756-762
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    • 2006
  • Shape Memory Alloy(SMA) actuators, which have the ability to return to a predetermined shape when heated, have many potential applications such as aeronautics, surgical tools, robotics and so on. Although the conventional PID controller can be used with slow response systems, there has been limited success in precise motion control of SMA actuators, since the systems are disturbed by unknown factors beside their inherent nonlinear hysteresis and changes in the surrounding environment of the systems. This paper presents a new development of a SMA position control system by using a self-tuning fuzzy PID controller. This control algorithm is used by tuning the parameters of the PID controller thereby integrating fuzzy inference and producing a fuzzy adaptive PID controller, which can then be used to improve the control performance of nonlinear systems. The experimental results of position control of SMA actuators using conventional and self-tuning fuzzy PID controllers are both included in this paper.

Patch-based Texture Synthesis for Marker Concealment (마커 은닉을 위한 패치 기반 텍스쳐 합성)

  • Yun, Kyung-Dahm;Woo, Woon-Tack
    • Journal of the HCI Society of Korea
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    • v.2 no.2
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    • pp.11-18
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    • 2007
  • We propose a novel method to conceal fiducial markers observed in augmented scenes using patch-based texture synthesis. Despite the efficiency for simple object recognition and tracking, the markers deliver inherent obtrusiveness. They do not only reduce immersiveness, but also severely degrade usability of augmented reality. The proposed method constructs alternative images in real time to overlay markers present in the sequence of images. The global characteristics of background textures are retained and the results are more adaptive to illumination changes.

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Design of a Controller for the Heat Capacity of Thermal Storage Systems Using Off-Peak Electricity (축열식 심야전력기기를 위한 축열량 제어기 설계)

  • Lee, Eun-Uk;Yang, Hae-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.1
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    • pp.1211-1217
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    • 2001
  • This paper presnts a controller for the heat capacity of thermal storage systems using off-peak electricity which is composed of an identifier using neural networks and a storage time adjuster in order to store exactly the required thermal energy without loss. Since thermal storage systems have nonlinear characteristics and large time constant, even if we predict the heating load accurately, it is very difficult to store exactly the required thermal energy. Thus, in the neural network for the identifier, the adaptive learning rate for high learning speed and bit inputs based on state changes of thermal storage power source are used. Also a hardware for the controller using a microprocessor is developed. The performance of the proposed controller is shown by experiment.

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PID Control of Poly-butadiene Latex(PBL) Reactor Based on Closed-loop Identification and Genetic Algorithm

  • Kwon, Tae-In;Yeo, Yeong-Koo;Lee, Kwang Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2600-2605
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    • 2003
  • The PBL (Poly-butadiene Latex) production process is a typical batch process. Changes of the reactor characteristics due to the accumulated scaling with the increase of batch cycles require adaptive tuning of the PID controller being used. In this work we propose a tuning method for PID controllers based on the closed-loop identification and the genetic algorithm (GA) and apply it to control the PBL process. An approximated process transfer function for the PBL reactor is obtained from the closed-loop data using a suitable closed-loop identification method. Tuning is performed by GA optimization in which the objective function is given by ITAE for the setpoint change. The proposed tuning method showed good control performance in actual operations.

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A Study on Adaptive Routing Algorithm for Changing Environment in Sensor Networks (Sensor Network 환경에서 저전력 기반의 적응적 라우팅 알고리즘 연구)

  • Jun, Jae-Sung;Yang, Hyun-Gyu;Rhee, Byung-Ho
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.1043-1048
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    • 2005
  • As sensor network is drawing more attention than ever before due to the development of sensors and the technology of communications, various routing-algorithms, to realize a sensor node with low-power and a miniature size, is being introduced in the field. This paper is to discuss a way to find an optimal path by changing a routing- algorithm adequately according to environmental changes. This is also to suggest an appropriate sensor network model in the ubiquitous aera. The result from the experiment that we conducted showed us that as we suggested, an algorithm, changing and adapting itself to each different environment, operated more stably and transmitted data more effectively than the current fixed one. And it was also confirmed that this type of algorithm can provide low-power management, which is very important in sensor network.

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Correction Method of Movement Path for Depth Touch by Adaptive Filter (적응적 필터를 통한 깊이 터치에 대한 움직임 경로의 보정 방법)

  • Lee, Dong-Seok;Kwon, Soon-Kak
    • Journal of Korea Multimedia Society
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    • v.19 no.10
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    • pp.1767-1774
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    • 2016
  • In this paper, we propose the adaptation filtering for correcting the movement path of the recognized object by the depth information. When we recognize the object by the depth information, the path error should be occurred because of the noises in the depth information. The path error is corrected by appling the lowpass filtering, but the lowpass filtering is not efficient when the changes of the object's movement are rapid. In this paper, we apply the adaptation filtering that it gives weights adaptively as the difference between the predicted location and the measured location. To apply the adaptation filtering, we can see that the proposed method can correct accurately the path error of the radical change from simulation results.

Image-guided radiation therapy in lymphoma management

  • Eng, Tony;Ha, Chul S.
    • Radiation Oncology Journal
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    • v.33 no.3
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    • pp.161-171
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    • 2015
  • Image-guided radiation therapy (IGRT) is a process of incorporating imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), Positron emission tomography (PET), and ultrasound (US) during radiation therapy (RT) to improve treatment accuracy. It allows real-time or near real-time visualization of anatomical information to ensure that the target is in its position as planned. In addition, changes in tumor volume and location due to organ motion during treatment can be also compensated. IGRT has been gaining popularity and acceptance rapidly in RT over the past 10 years, and many published data have been reported on prostate, bladder, head and neck, and gastrointestinal cancers. However, the role of IGRT in lymphoma management is not well defined as there are only very limited published data currently available. The scope of this paper is to review the current use of IGRT in the management of lymphoma. The technical and clinical aspects of IGRT, lymphoma imaging studies, the current role of IGRT in lymphoma management and future directions will be discussed.