321 research outputs found

    Formation control for cooperative surveillance

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    Constructing and maintaining a formation is critical in applications of cooperative control of multi-agent systems. In this research we address the formation control problem of generating a formation for a group of nonholonomic mobile agents. The formation control scheme proposed in this work is based on a fusion of leader-follower and virtual reference approaches. This scheme gives a formation constraint representation that is independent of the number of agents in the formation and the resulting control algorithm is scalable. One of the important desired features in controller design is that the formation errors defined by formation constraints should be stabilized globally and exponentially by the controller. The proposed controller is based on feedback linearization, and formation errors are shown to be globally exponentially stable in the sense of Lyapunov. Since formation errors are stabilized globally, the proposed controller is applicable to both formation keeping and formation construction problems. As a possible application, the proposed algorithm is implemented in a cooperative ground moving target surveillance scenario. The proposed algorithm enables the determination of the minimal number of agents required for surveillance of a moving target. The number of agents returned by this scheme is not optimal and hence is a conservative solution. However, this is justified by the computational savings the scheme offers

    A Magneto-Mechanical Piezoelectric Energy Harvester Designed to Scavenge AC Magnetic Field from Thermal Power Plant with Power-Line Cables

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    Piezoelectric energy harvesters have attracted much attention because they are crucial in portable industrial applications. Here, we report on a high-power device based on a magneto-mechanical piezoelectric energy harvester to scavenge the AC magnetic field from a power-line cable for industrial applications. The electrical output performance of the harvester (×4 layers) reached an output voltage of 60.8 Vmax, an output power of 215 mWmax (98 mWrms), and a power density of 94.5 mWmax/cm3 (43.5 mWrms/cm3) at an impedance matching of 5 kΩ under a magnetic field of 80 μT. The multilayer energy harvester enables high-output performance, presenting an obvious advantage given this improved level of output power. Finite element simulations were also performed to support the experimental observations. The generator was successfully used to power a wireless sensor network (WSN) for use on an IoT device composed of a temperature sensor in a thermal power station. The result shows that the magneto-mechanical piezoelectric energy harvester (MPEH) demonstrated is capable of meeting the requirements of self-powered monitoring systems under a small magnetic field, and is quite promising for use in actual industrial applications

    A Flexible Piezoelectric Energy Harvester-Based Single-Layer WS2 Nanometer 2D Material for Self-Powered Sensors

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    A piezoelectric sensor is a typical self-powered sensor. With the advantages of a high sensitivity, high frequency band, high signal-to-noise ratio, simple structure, light weight, and reliable operation, it has gradually been applied to the field of smart wearable devices. Here, we first report a flexible piezoelectric sensor (FPS) based on tungsten disulfide (WS2) monolayers that generate electricity when subjected to human movement. The generator maximum voltage was 2.26 V, and the produced energy was 55.45 μJ of the electrical charge on the capacitor (capacity: 220 μF) when applying periodic pressing by 13 kg. The generator demonstrated here can meet the requirements of human motion energy because it generates an average voltage of 7.74 V (a knee), 8.7 V (a sole), and 4.58 V (an elbow) when used on a running human (weight: 75 kg). Output voltages embody distinct patterns for different human parts, the movement-recognition capability of the cellphone application. This generator is quite promising for smart sensors in human–machine interaction detecting personal movement

    Submerzni uzgoj i karakterizacija polisaharida iz gljive Grifola frondosa – primjena u kozmetičkoj industriji

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    Grifola frondosa (maitake) is traditionally called \u27the king of mushrooms\u27 and \u27the hen of the woods\u27. Both the fruiting bodies and the mycelium of maitake have been reported to have antitumor and antiviral activities. Recently, submerged culture processes have been developed, with the intention of providing opportunities for increased economic exploitation of maitake. Commonly the aim of these processes is to produce extracellular polysaccharides (EPS), mostly glucans, and to explore their applications, particularly in the cosmetic industry. A wide variety of EPS with different molecular chain length and chemical compositions are produced under different culture conditions. In this article, various biological and physicochemical properties of the EPS of G. frondosa (GF-EPS) are described, with a view to applications in the area of functional cosmeceuticals. The GF-EPS, together with GF mycelial extract (GF-MPS), showed antioxidative activity, stimulation of collagen biosynthetic activity, cell proliferation activity, and inhibitory activity of melanogenesis, without significant cytotoxicity. These diverse functionalities suggest that both GF-EPS and GF-MPS can be promising cosmetic ingredients.Gljivu Grifola frondosa (maitake) u Koreji tradicionalno zovu kraljicom gljiva i šumskim bogatstvom. Dokazano je da plodište i micelij gljiva maitake imaju antitumorski i antivirusni učinak. Ekonomsko iskorištenje te gljive omogućeno je submerznim uzgojem. Uobičajeni je cilj uzgoja proizvodnja ekstracelularnih polisaharida (EPS), uglavnom glukana i istraživanje mogućnosti njihove primjene u kozmetičkoj industriji. Pri raznim uvjetima proizvodnje dobivaju se ekstracelularni polisaharidi različitih duljina lanaca i kemijskoga sastava. U ovom su radu opisana razna biološka i fizikalno-kemijska svojstva ekstracelularnih polisaharida gljive Grifola frondosa (GF-EPS), te primjena u proizvodnji kozmetičkih preparata s povoljnim utjecajem na ljudsko zdravlje. Ekstracelularni polisaharidi i ekstrakt micelija gljive Grifola frondosa (GFMPS) imaju antioksidativni učinak, stimuliraju biosintezu kolagena, bujanje stanica, sprečavaju nastanak melanoma i nemaju jače citotoksično djelovanje, zbog čega su prikladni za primjenu u kozmetičkoj industriji

    Peutz-Jeghers Syndrome with Multiple Genital Tract Tumors and Breast Cancer: A Case Report with a Review of Literatures

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    We report here on the multiple genital tract neoplasms in a 41-yr-old Korean woman with Peutz-Jeghers Syndrome (PJS). The patient presented with lower abdominal pain. Her previous medical history was PJS and breast cancer. Pelvic ultrasound showed a multilocular cyst at the right adnexal region, diagnosed as bilateral ovarian mucinous borderline tumors. An ovarian sex cord tumor with annular tubules was incidentally diagnosed together with a minimal deviation adenocarcinoma of the uterine cervix and mucinous metaplasia of both the Fallopian tubal mucosa and the endometrium. Although the cases of multiple genital tract tumors with PJS has rarely been reported, the present case appears to be the first in Korea in which the PJS syndrome was complicated by multiple genital tract tumors and infiltrating carcinoma of the breast. The clinical significance of the multiple genital tract tumors and breast cancer associated with PJS is reviewed

    Favorable prognosis in colorectal cancer patients with co-expression of c-MYC and ß-catenin

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background The purpose of our research was to determine the prognostic impact and clinicopathological feature of c-MYC and β-catenin overexpression in colorectal cancer (CRC) patients. Methods Using immunohistochemistry (IHC), we measured the c-MYC and β-catenin expression in 367 consecutive CRC patients retrospectively (cohort 1). Also, c-MYC expression was measured by mRNA in situ hybridization. Moreover, to analyze regional heterogeneity, three sites of CRC including the primary, distant and lymph node metastasis were evaluated in 176 advanced CRC patients (cohort 2). Results In cohort 1, c-MYC protein and mRNA overexpression and ß-catenin nuclear expression were found in 201 (54.8 %), 241 (65.7 %) and 221 (60.2 %) of 367 patients, respectively, each of which was associated with improved prognosis (P = 0.011, P = 0.012 and P = 0.033, respectively). Moreover, co-expression of c-MYC and ß-catenin was significantly correlated with longer survival by univariate (P = 0.012) and multivariate (P = 0.048) studies. Overexpression of c-MYC protein was associated with mRNA overexpression (ρ, 0.479; P  0.05). Conclusions Co-expression of c-MYC and ß-catenin was independently correlated with favorable prognosis in CRC patient. We concluded that the expression of c-MYC and ß-catenin might be useful predicting indicator of CRC patients prognosis
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