38 research outputs found

    Isometric Motion Manifold Primitives

    Full text link
    The Motion Manifold Primitive (MMP) produces, for a given task, a continuous manifold of trajectories each of which can successfully complete the task. It consists of the decoder function that parametrizes the manifold and the probability density in the latent coordinate space. In this paper, we first show that the MMP performance can significantly degrade due to the geometric distortion in the latent space -- by distortion, we mean that similar motions are not located nearby in the latent space. We then propose {\it Isometric Motion Manifold Primitives (IMMP)} whose latent coordinate space preserves the geometry of the manifold. For this purpose, we formulate and use a Riemannian metric for the motion space (i.e., parametric curve space), which we call a {\it CurveGeom Riemannian metric}. Experiments with planar obstacle-avoiding motions and pushing manipulation tasks show that IMMP significantly outperforms existing MMP methods. Code is available at https://github.com/Gabe-YHLee/IMMP-public.Comment: 8 pages, 13 figures. This work has been submitted to the IEEE for possible publicatio

    FoX: Formation-aware exploration in multi-agent reinforcement learning

    Full text link
    Recently, deep multi-agent reinforcement learning (MARL) has gained significant popularity due to its success in various cooperative multi-agent tasks. However, exploration still remains a challenging problem in MARL due to the partial observability of the agents and the exploration space that can grow exponentially as the number of agents increases. Firstly, in order to address the scalability issue of the exploration space, we define a formation-based equivalence relation on the exploration space and aim to reduce the search space by exploring only meaningful states in different formations. Then, we propose a novel formation-aware exploration (FoX) framework that encourages partially observable agents to visit the states in diverse formations by guiding them to be well aware of their current formation solely based on their own observations. Numerical results show that the proposed FoX framework significantly outperforms the state-of-the-art MARL algorithms on Google Research Football (GRF) and sparse Starcraft II multi-agent challenge (SMAC) tasks.Comment: 7 pages main, 5 pages appendix with reference. 10 figures, submitted for AAA

    Economical And Systematical Evaluation On Rainfall Harvesting System (Case Study : Rainfall Harvesting System Designed In Taebaek City, Republic Of Korea)

    Full text link
    Recently, climate change has caused drought to become more frequent and is becoming one of the serious natural disasters, resulting damages in infrastructure facilities, economy and private property losses etc. Taebaek city of Gangwon-do lies in the northeast Korean Peninsula along the steep mountain slopes, all the way to the sea. Thu, this city exhibit the Marine Climatic Characteristics. During the past 10 years, the average rainfall of Taebaek city is 849.9mm/year, which is less than the average rainfall for the whole country (1,274mm/year). This research is still ongoing. The next assessment will be on the construction cost of rainfall harvesting system (through school types) and the LCC (Life Cycle Cost) of Maintenance Administration. After which, discussion for the impacts Rainfall Harvesting System on the water supply self-sufficiency of Taeback city will be made. Lastly, conclusion on the future economic benefit for Taeback city will be given. ACKNOWLEDGEMENT This research was supported by a grant(12-TI-C01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean governmen

    An Analysis Of Discharge And Water Level Changes Due To Weir (In The Case Of The Waegwan And Nakdong Station In South Korea)

    Full text link
    ABSTRACT Our country, Korea, lacks the per capita water endowment because of the high population density and geographical characteristics. Therefore, The 4 Rivers Project has been promoted since 2009. In order to control effectively drought or floods caused by abnormal climate and strong rainfall in summer, it was done and completed in 2013. The Nakdong River is the longest in the 4 Rivers Project, which it was conducted among the country\u27s major rivers, and a lot of hydraulic structures were installed. we selected Nakdong and Weagwan stations which are located in the Nakdong River. Because the change was smaller there with the inflow of tributaries flow than elsewhere. And many hydraulic structures were installed between Nakdong and Weagwan stations, which used T/M machine to collect real-time data. In this study, we compared and analyzed the flow change of real-time and water level data of prior to weir installation on May, June, July, 2009 and completion of weir installation on May, June, July , 2013. The original purpose of installing the weir is well-kept. After installation of Hydraulic structures(weir), the discharge difference between the Nakdong Station and Weagwan Station was reduced , and both of Nakdong and Weagwan stations are almost maintain a constant value of water level without being affected by rainfall. Also, we could confirm that the maximum water-level variation is decreased after installation of the weir. Based on this, we judged that hydrological effects on drought or floods due to abnormal weather were decreased by the time of weir installation. ACKNOWLEDGEMENT This research was supported by a grant(12-TI-C01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean governmen

    Gene Expression Profile of the Hypothalamus in DNP-KLH Immunized Mice Following Electroacupuncture Stimulation

    Get PDF
    Clinical evidence indicates that electroacupuncture (EA) is effective for allergic disorder. Recent animal studies have shown that EA treatment reduces levels of IgE and Th2 cytokines in BALB/c mice immunized with 2,4-dinitrophenylated keyhole limpet protein (DNP-KLH). The hypothalamus, a brain center of the neural-immune system, is known to be activated by EA stimulation. This study was performed to identify and characterize the differentially expressed genes in the hypothalamus of DNP-KLH immunized mice that were stimulated with EA or only restrained. To this aim, we conducted a microarray analysis to evaluate the global gene expression profiles, using the hypothalamic RNA samples taken from three groups of mice: (i) normal control group (no treatments); (ii) IMH group (DNP-KLH immunization + restraint); and (iii) IMEA group (immunization + EA stimulation). The microarray analysis revealed that total 39 genes were altered in their expression levels by EA treatment. Ten genes, including T-cell receptor alpha variable region family 13 subfamily 1 (Tcra-V13.1), heat shock protein 1B (Hspa1b) and 2′–5′ oligoadenylate synthetase 1F (Oas1f), were up-regulated in the IMEA group when compared with the IMH group. In contrast, 29 genes, including decay accelerating factor 2 (Daf2), NAD(P)H dehydrogenase, quinone 1 (Nqo1) and programmed cell death 1 ligand 2 (Pdcd1lg2) were down-regulated in the IMEA group as compared with the IMH group. These results suggest that EA treatment can modulate immune response in DNP-KLH immunized mice by regulating expression levels of genes that are associated with innate immune, cellular defense and/or other kinds of immune system in the hypothalamus

    Horizontally Assembled Trapezoidal Piezoelectric Cantilevers Driven by Magnetic Coupling for Rotational Energy Harvester Applications

    No full text
    Horizontally assembled trapezoidal piezoelectric cantilevers driven by magnetic coupling were fabricated for rotational energy harvester applications. A dodecagonal rigid frame with an attached array of six trapezoidal cantilevers served as a stator for electrical power generation. A rotor disk with six permanent magnets (PMs) interacted magnetically with the counterpart cantilever’s tip-mass PMs of the stator by rotational motion. Each trapezoidal piezoelectric cantilever beam was designed to operate in a transverse mode that utilizes a planar Ag/Pd electrode printed onto lead zirconate titanate (PZT) piezoelectric thick film. The optimized distance between a pair of PMs of the rotor and the stator was evaluated as approximately 10 mm along the same vertical direction to make the piezoelectric cantilever beam most deflectable without the occurrence of cracks. The theoretically calculated resistance torque was maximized at 46 mN·m for the optimized trapezoidal piezoelectric cantilever. The proposed energy harvester was also demonstrated for wind energy harvester applications. Its harvested output power reached a maximum of approximately 22 mW at a wind speed of 10 m/s under a resistive load of 30 kΩ. The output performance of the proposed energy harvester makes it possible to power numerous low-power applications such as smart sensor systems

    Synthesis of Pyrazines from Rhodium-Catalyzed Reaction of 2<i>H</i>‑Azirines with <i>N</i>‑Sulfonyl 1,2,3-Triazoles

    No full text
    An efficient synthetic route to a wide range of trisubstituted pyrazines is developed from Rh-catalyzed reaction of 2<i>H</i>-azirines with <i>N</i>-sulfonyl-1,2,3-triazoles through the elimination of nitrogen molecule and arylsulfinic acid. The present reaction proceeds through formation of <i>in situ</i> generated dihydropyrazines

    Exploiting volumetric wave correlation for enhanced depth imaging in scattering medium

    No full text
    The authors achieve ultrahigh resolution and depth volumetric imaging in complex media by recording a volumetric reflection matrix covering individual wavelengths and angles and developing reconstruction algorithms based on volumetric wave correlation

    Immunomodulatory and Anti-inflammatory Effects of Asiatic Acid in a DNCB-Induced Atopic Dermatitis Animal Model

    No full text
    We examined the immunomodulatory and anti-inflammatory effects of asiatic acid (AA) in atopic dermatitis (AD). AA treatment (5–20 µg/mL) dose-dependently suppressed the tumor necrosis factor (TNF)-α level and interleukin (IL)-6 protein expression in interferon (IFN)-γ + TNF-α-treated HaCaT cells. The 2,4-dinitrocholrlbenzene (DNCB)-induced AD animal model was developed by administering two AA concentrations (30 and 75 mg/kg/d: AD + AA-L and AD + AA-H groups, respectively) for 18 days. Interestingly, AA treatment decreased AD skin lesions formation and affected other AD characteristics, such as increased ear thickness, lymph node and spleen size, dermal and epidermal thickness, collagen deposition, and mast cell infiltration in dorsal skin. In addition, in the DNCB-induced AD animal model, AA treatment downregulated the mRNA expression level of AD-related cytokines, such as Th1- (TNF-α and IL-1β and -12) and Th2 (IL-4, -5, -6, -13, and -31)-related cytokines as well as that of cyclooxygenase-2 and CXCL9. Moreover, in the AA treatment group, the protein level of inflammatory cytokines, including COX-2, IL-6, TNF-α, and IL-8, as well as the NF-κB and MAPK signaling pathways, were decreased. Overall, our study confirmed that AA administration inhibited AD skin lesion formation via enhancing immunomodulation and inhibiting inflammation. Thus, AA can be used as palliative medication for regulating AD symptoms
    corecore