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1.
Arch Psychiatr Nurs ; 43: 118-126, 2023 04.
Article in English | MEDLINE | ID: mdl-37032005

ABSTRACT

This study developed and evaluated an online mental health program for female college students who experienced trauma, based on Roy's Adaptation Model. A randomized controlled trial was adopted. Participants completed a survey on trauma and post-traumatic stress symptoms. Data from experimental and control groups (n = 16) were collected over two months. The program reduced post-traumatic stress and depression symptoms and improved functional health and adjustment. This effect was sustained in experimental group participants for one month post-program. The findings revealed the effectiveness of Internet mental healthcare for female students and the crucial role nurses play in it.


Subject(s)
Mental Health , Students , Humans , Female , Students/psychology , Surveys and Questionnaires , Delivery of Health Care , Internet
2.
Sensors (Basel) ; 22(10)2022 May 10.
Article in English | MEDLINE | ID: mdl-35632026

ABSTRACT

A modified sigmoid sliding mode control (MS-SMC) approach is proposed for stabilizing and tracking a quadrotor system with a nonlinear sliding surface, where the dynamics model is underactuated, highly coupled, and nonlinear. The constructed nonlinear sliding surface is based on the traditional sliding mode surface with a modified sigmoid function, allowing the initial value to quickly reach equilibrium. A new type of nonlinear SMC is applied for performance improvement of the quadrotor using the proposed modified sigmoid sliding surface. To control the quadrotor effectively, a double-loop control method is used to design the control rate, in which the position subsystem is the outer loop, and the attitude subsystem is the inner loop.With the Lyapunov function, the stability of the overall closed-loop system is ensured by stabilizing each subsystem step by step. Moreover, from a practical point of view, the system performance under the model uncertainties and external disturbances are also considered. The simulation results show that the proposed MS-SMC performs better than the conventional sliding mode control (CSMC) and the back-stepping sliding mode control (BS-SMC) in terms of stabilization and tracking against external disturbances.

3.
Sensors (Basel) ; 22(6)2022 Mar 13.
Article in English | MEDLINE | ID: mdl-35336390

ABSTRACT

The discrimination between earthquakes and artificial explosions is a significant issue in seismic analysis to efficiently prevent and respond to seismic events. However, the discrimination of seismic events is challenging due to the low incidence rate. Moreover, the similarity between earthquakes and artificial explosions with a local magnitude derives a nonlinear data distribution. To improve the discrimination accuracy, this paper proposes machine-learning-based seismic discrimination methods-support vector machine, naive Bayes, and logistic regression. Furthermore, to overcome the nonlinear separation problem, the kernel functions and regularized logistic regression are applied to design seismic classifiers. To efficiently design the classifier, P- and S-wave amplitude ratios on the time domain and spectral ratios on the frequency domain, which is converted by fast Fourier transform and short-time Fourier transform are selected as feature vectors. Furthermore, an adaptive synthetic sampling algorithm is adopted to enhance the classifier performance against the seismic data imbalance issue caused by the non-equivalent number of occurrences. The comparisons among classifiers are evaluated by the binary classification performance analysis methods.

4.
Vet Med (Praha) ; 67(10): 538-543, 2022 Oct.
Article in English | MEDLINE | ID: mdl-38846426

ABSTRACT

A 19-month-old Korean native cow died the following day after consuming new silage. Grossly, the liver showed enlargement, redness, and haemorrhages in all the lobes. Additionally, many of the bur-shaped fruits of the cocklebur (Xanthium strumarium) were found in the gastric contents. The histological evaluation confirmed centrilobular hepatic necrosis. Additionally, carboxyatractyloside (CATR), a material fatal to animals found in the cocklebur, was detected in the gastric contents using high-performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF-MS). Based on the pathological findings and analytical confirmation, CATR intoxication was diagnosed. Therefore, careful feeding and elimination of the cocklebur is essential for minimising economic loss.

5.
Sensors (Basel) ; 21(1)2021 Jan 02.
Article in English | MEDLINE | ID: mdl-33401778

ABSTRACT

Among various localization methods, a localization method that uses a radio frequency signal-based wireless sensor network has been widely applied due to its robustness against noise factors and few limits on installation location. In this paper, we focus on an iterative localization scheme for a mobile with a limited number of time difference of arrival (TDOA) and angle of arrival (AOA) data measured from base stations. To acquire the optimal location of a mobile, we propose a recursive solution for localization using an iteratively reweighted-recursive least squares (IR-RLS) algorithm. The proposed IR-RLS scheme can obtain the optimal solution with a fast computational speed when additional TDOA and/or AOA data is measured from base stations. Moreover, while the number of measured TDOA/AOA data was limited, the proposed IR-RLS scheme could obtain the precise location of a mobile. The performance of the proposed IR-RLS method is confirmed through some simulation results.

6.
Sensors (Basel) ; 20(7)2020 Mar 28.
Article in English | MEDLINE | ID: mdl-32231075

ABSTRACT

The discrimination between earthquakes and explosions is a serious issue in seismic signal analysis. This paper proposes a seismic discrimination method using support vector machine (SVM), wherein the amplitudes of the P-wave and the S-wave of the seismic signals are selected as feature vectors. Furthermore, to improve the seismic discrimination performance using a heterodyne laser interferometer for seismic wave detection, the Hough transform is applied as a compensation method for the periodic nonlinearity error caused by the frequency-mixing in the laser interferometric seismometer. In the testing procedure, different kernel functions of SVM are used to discriminate between earthquakes and explosions. The outstanding performance of a laser interferometer and Hough transform method for precision seismic measurement and nonlinearity error compensation is confirmed through some experiments using a linear vibration stage. In addition, the effectiveness of the proposed discrimination method using a heterodyne laser interferometer is verified through a receiver operating characteristic curve and other performance indices obtained from practical experiments.

7.
Sensors (Basel) ; 19(6)2019 Mar 25.
Article in English | MEDLINE | ID: mdl-30934582

ABSTRACT

In this paper, a heterodyne laser interferometer, which is used as a sensor for high-precision displacement measurement, is introduced to measure ground vibration and seismic waves as a seismometer. The seismic wave is measured precisely through the displacement variation obtained by the heterodyne laser interferometer. The earthquake magnitude is estimated using only the P-wave magnitudes for the first 3 s through the total noise enhanced optimization (TNEO) model. We use data from southern California to investigate the relationship between peak acceleration amplitude ( P d ) and the earthquake magnitude ( M g ). For precise prediction of the earthquake magnitude using only the P d value, the TNEO model derives the relation equation between P d and the magnitude, considering the noise present in each measured seismic data. The optimal solution is obtained from the TNEO model based objective function. We proved the performance of the proposed method through simulation and experimental results.

8.
Korean J Parasitol ; 57(1): 17-20, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30840794

ABSTRACT

A stray female cat of unknown age, presenting bright red watery diarrhea, was submitted to the Animal and Plant Quarantine Agency for diagnosis. In the small intestines extracted from the necropsied cat, numerous white oval-shaped organisms were firmly embedded in the mucosa and there was thickening of intestinal wall. Histopathological analysis revealed severe necrotizing enteritis, together with atrophied intestinal villi, exfoliated enterocytes, and parasitic worms. Recovered worms were identified as Pharyngostomum cordatum by morphological observation and genetic analysis. Although P. cordatum is known to occur widely in Korea, this is the first clinical description of an infection by P. cordatum causing severe feline enteritis.


Subject(s)
Cat Diseases/diagnosis , Cat Diseases/pathology , Diarrhea/veterinary , Enterocolitis, Necrotizing/veterinary , Trematoda/isolation & purification , Trematode Infections/veterinary , Animals , Cat Diseases/parasitology , Cats , Diarrhea/diagnosis , Diarrhea/parasitology , Diarrhea/pathology , Enterocolitis, Necrotizing/diagnosis , Enterocolitis, Necrotizing/parasitology , Enterocolitis, Necrotizing/pathology , Female , Histocytochemistry , Intestinal Mucosa/parasitology , Intestinal Mucosa/pathology , Intestine, Small/parasitology , Intestine, Small/pathology , Korea , Trematoda/anatomy & histology , Trematoda/genetics , Trematode Infections/diagnosis , Trematode Infections/parasitology , Trematode Infections/pathology
9.
Emerg Infect Dis ; 24(12): 2343-2347, 2018 12.
Article in English | MEDLINE | ID: mdl-30457524

ABSTRACT

In December 2016, highly pathogenic avian influenza (HPAI) infection with systemic pathologic lesions was found in cats in South Korea. Genetic analyses indicated that the feline isolates were similar to HPAI H5N6 viruses isolated in chicken farms nearby. This finding highlights the need for monitoring of domestic mammals during HPAI outbreaks.


Subject(s)
Cat Diseases/epidemiology , Cat Diseases/virology , Influenza A virus/genetics , Animals , Biopsy , Cat Diseases/diagnosis , Cats , Disease Outbreaks , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A virus/classification , Influenza A virus/pathogenicity , Lung/pathology , Lung/virology , Male , Phylogeny , RNA, Viral , Republic of Korea/epidemiology
10.
Virol J ; 15(1): 115, 2018 07 28.
Article in English | MEDLINE | ID: mdl-30055639

ABSTRACT

BACKGROUND: Bovine viral diarrhea virus (BVDV) causes significant economic losses worldwide in the cattle industry through decrease in productive performance and immunosuppression of animals in herds. Recent studies conducted by our group showed that mice can be infected with BVDV-1 by the oral route. The purpose of this study was to assess the clinical signs, hematological changes, histopathological lesions in lymphoid tissues, and the distribution of the viral antigen after oral inoculation with a Korean noncytopathic (ncp) BVDV-2 field isolate in mice. METHODS: Mice were orally administered a low or high dose of BVDV-2; blood and tissue samples were collected on days 2, 5, and 9 postinfection (pi). We monitored clinical signs, hematological changes, histopathological lesions, and tissue distribution of a viral antigen by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) and then compared these parameters with those in ncp BVDV-1 infections. RESULTS: None of the infected mice developed any clinical signs of the illness. Significant thrombocytopenia was found in both low- and high-dose-inoculated mice on day 2 pi. Leukopenia was apparent only in low-dose-inoculated mice on day 2 pi, whereas lymphopenia was not observed in any ncp BVDV-2-infected animal. Viral RNA was found in the spleen in of low- and high-dose-inoculated mice by RT-PCR. According to the results of IHC, the viral antigen was consistently detected in lymphocytes of bone marrow and spleen and less frequently in bronchus-associated lymphoid tissue (BALT), mesenteric lymph nodes, and Peyer's patches. Despite the antigen detection in BALT and mesenteric lymph nodes, histopathological lesions were not observed in these tissues. Lympholysis, infiltration by inflammatory cells, and increased numbers of megakaryocytes were seen in Peyer's patches, spleens, and bone marrow, respectively. In contrast to ncp BVDV-1 infection, lympholysis was found in the spleen of ncp BVDV-2-infected mice. These histopathological lesions were more severe in high-dose-inoculated mice than in low-dose-inoculated mice. CONCLUSIONS: Our results provide insight into the pathogenesis of ncp BVDV-2 infection in mice. Collectively, these results highlight significant differences in pathogenesis between ncp BVDV-1 and ncp BVDV-2 infections in a murine model.


Subject(s)
Bone Marrow/pathology , Diarrhea Virus 2, Bovine Viral/physiology , Megakaryocytes/pathology , Megakaryocytes/virology , Pestivirus Infections/pathology , Pestivirus Infections/virology , Animals , Cattle , Disease Models, Animal , Hemorrhagic Syndrome, Bovine/blood , Hemorrhagic Syndrome, Bovine/pathology , Hemorrhagic Syndrome, Bovine/virology , Mice , Pestivirus Infections/blood , Peyer's Patches/pathology , Peyer's Patches/virology , RNA, Viral , Spleen/pathology , Spleen/virology , Viral Load
11.
Sensors (Basel) ; 17(10)2017 Oct 23.
Article in English | MEDLINE | ID: mdl-29065515

ABSTRACT

In this paper, we suggest a seismic signal measurement system that uses a laser interferometer. The heterodyne laser interferometer is used as a seismometer due to its high accuracy and robustness. Seismic data measured by the laser interferometer is used to analyze crucial earthquake characteristics. To measure P-S time more precisely, the short time Fourier transform and instantaneous frequency estimation methods are applied to the intensity signal ( I y ) of the laser interferometer. To estimate the epicenter location, the range difference of arrival algorithm is applied with the P-S time result. The linear matrix equation of the epicenter localization can be derived using P-S time data obtained from more than three observatories. We prove the performance of the proposed algorithm through simulation and experimental results.

12.
Arch Virol ; 161(2): 417-24, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26526150

ABSTRACT

Here, we infected mice with cytopathic bovine viral diarrhea virus 1 (cp BVDV1) by oral inoculation and investigated the effects of infection by histopathological, immunohistochemical (IHC), hematological methods. Twelve mice were infected, and samples were obtained at day 2, 5, and 9 postinfection (pi). Most of the infected mice exhibited clinical signs of illness such as reduced movement, crouching, loose feces, loss of appetite, and reduced water intake. Blood samples from six mice were positive for BVDV based on reverse transcription polymerase chain reaction (RT-PCR). Blood analysis also revealed thrombocytopenia and lymphopenia. Viral antigens were detected in the spleen (12/12), bone marrow (12/12), and/or mesenteric lymph nodes (4/12) of all infected mice by IHC analysis. The spleens showed significant histopathological changes including (i) substantially increased numbers of megakaryocytes, (ii) lymphocyte depletion, and (iii) hemorrhages. The bone marrow also had an increased number of megakaryocytes, although this increase was not as strong as it was in the spleen. Severe lymphoid depletion was observed in the mesenteric lymph nodes. Viral infections were present in the lymphocytes but not detected in megakaryocytes of the spleen, bone marrow, or mesenteric lymph nodes. These results suggest that the increased numbers of megakaryocytes may be a direct result of BVDV infection. BVDV infection in mice following oral inoculation of cp BVDV1 leads to megakaryopoiesis in the spleen and bone marrow to replenish the platelets.


Subject(s)
Bone Marrow/pathology , Bovine Virus Diarrhea-Mucosal Disease/pathology , Diarrhea Viruses, Bovine Viral/physiology , Spleen/pathology , Thrombopoiesis , Animal Structures/pathology , Animal Structures/virology , Animals , Antigens, Viral/analysis , Bone Marrow/virology , Cattle , Disease Models, Animal , Histocytochemistry , Immunohistochemistry , Mice , Spleen/virology
13.
Arch Virol ; 161(2): 395-403, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26586332

ABSTRACT

Bovine viral diarrhea virus (BVDV) is an economically important pathogen that causes development of mild to severe clinical signs in wild and domesticated ruminants. We previously showed that mice could be infected by BVDV. In the present study, we infected mice intraperitoneally with non-cytopathic (ncp) BVDV1 or ncp BVDV2, harvested the blood and organs of the infected mice at days 4, 7, 10 and 14 postinfection (pi), and performed immunohistochemical analyses to confirm BVDV infection. Viral antigens were detected in the spleens of all infected mice from days 4 through 14 and were also found in the mesenteric lymph nodes, gut-associated lymphoid tissue (GALT), heart, kidney, intestine, and bronchus-associated lymphoid tissue (BALT) of some infected mice. In ncp BVDV2-infected mice, flow cytometric analysis revealed markedly fewer CD4(+) and CD8(+) T lymphocytes and lower expression of costimulatory molecules CD80 (B7-1) and CD86 (B7-2) and major histocompatibility complex (MHC) class II (I-A/I-E) than those in ncp BVDV1-infected mice. Production of the cytokines interleukin (IL)-6 and monocyte chemotactic protein (MCP)-1 was higher in the plasma of ncp BVDV2-infected mice than that in that of ncp BVDV1-infected mice. Our results demonstrate that ncp BVDV1 and ncp BVDV2 interact differently with the host innate immune response in vivo. These findings highlight an important distinction between ncp BVDV1 and ncp BVDV2 and suggest that ncp BVDV2 impairs the host's ability to control the infection and enhances virus dissemination.


Subject(s)
Diarrhea Virus 2, Bovine Viral/immunology , Diarrhea Virus 2, Bovine Viral/pathogenicity , Pestivirus Infections/pathology , Pestivirus Infections/virology , Animal Structures/virology , Animals , Antigens, Viral/analysis , Disease Models, Animal , Flow Cytometry , Immune Tolerance , Immunohistochemistry , Injections, Intraperitoneal , Mice , Pestivirus Infections/immunology , T-Lymphocyte Subsets/immunology
14.
Arch Virol ; 161(9): 2527-35, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27376375

ABSTRACT

Previously, our study showed that oral inoculation of mice with cytopathic (cp) bovine viral diarrhea virus (BVDV) led to lymphocyte depletion and increased numbers of megakaryocytes in the spleen as well as thrombocytopenia and lymphopenia. In the present study, to investigate the possible differences in the detection of viral antigen, histopathological lesions, and hematologic changes between non-cytopathic (ncp) BVDV1 and cp BVDV1, mice were orally administered low and high doses of ncp BVDV1 and were necropsied at days 0, 2, 5, and 9 postinfection (pi). None of the ncp BVDV1-infected mice exhibited clinical signs of illness, unlike those infected with cp BVDV1. Statistically significant thrombocytopenia was observed during ncp BVDV1 infection, and lymphopenia was found only in mice infected with a high dose at day 9 pi. Interestingly, ncp BVDV1 infection increased the numbers of basophils, eosinophils, neutrophils, and monocytes in some infected mice. Viral antigen was detected in the lymphocytes of the spleen, mesenteric lymph nodes, Peyer's patches, and bone marrow by immunohistochemistry. Lymphoid depletion was evident in the mesenteric lymph nodes of mice infected with a high dose and also found in the Peyer's patches of some infected mice. Infiltration of inflammatory cells, including neutrophils and monocytes, and an increased number of megakaryocytes were seen in the spleen. These results suggest that the distribution of viral antigens is not associated with the presence of histopathological lesions. Inflammatory cell infiltration was observed in the spleens as a result of viral replication and may be attributable to the host reaction to ncp BVDV1 infection. Together, these findings support the possibility that mice can be used as an animal model for BVDV infection.


Subject(s)
Diarrhea Virus 1, Bovine Viral/pathogenicity , Leukocytes/physiology , Pestivirus Infections/virology , Spleen/cytology , Animals , Mice , Mice, Inbred BALB C , Pestivirus Infections/pathology , Specific Pathogen-Free Organisms , Spleen/virology
15.
Emerg Infect Dis ; 21(5): 775-80, 2015 May.
Article in English | MEDLINE | ID: mdl-25897841

ABSTRACT

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. To determine the causes of death, we examined 771 wild bird carcasses and identified HPAI A(H5N8) virus in 167. Gross and histologic lesions were observed in pancreas, lung, brain, and kidney of Baikal teals, bean geese, and whooper swans but not mallard ducks. Such lesions are consistent with lethal HPAI A(H5N8) virus infection. However, some HPAI-positive birds had died of gunshot wounds, peritonitis, or agrochemical poisoning rather than virus infection. These findings suggest that susceptibility to HPAI A(H5N8) virus varies among species of migratory birds and that asymptomatic migratory birds could be carriers of this virus.


Subject(s)
Influenza A virus/classification , Influenza A virus/genetics , Influenza in Birds/epidemiology , Influenza in Birds/virology , Animals , Animals, Wild , Birds , Disease Outbreaks , Genotype , History, 21st Century , Influenza A virus/pathogenicity , Influenza in Birds/diagnosis , Influenza in Birds/history , Republic of Korea/epidemiology
16.
Arch Virol ; 160(6): 1565-71, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25850760

ABSTRACT

The objective of this study was to test the ability of bovine viral diarrhea virus (BVDV) to infect mice. Two mice each were either mock infected or inoculated with one of three BVDV strains by the intraperitoneal (IP) (n = 8) or intranasal (IN) (n = 8) route. All mice were euthanized at day 7 postinfection (p.i.). None of the infected mice exhibited any clinical signs of illness; however, the tissues harvested after BVDV challenge showed significant histopathological changes. Blood samples from five mice that were injected IP and one mouse that was inoculated IN were positive for BVDV by reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemistry (IHC) was used to assess the presence of viral antigen in the organs of mice infected with three BVDV strains. In IP-injected mice, BVDV antigen was detected in the spleen (5/6), mesenteric lymph nodes (4/6), lymphatic tissue of the lung (3/6), lung (1/6), and stomach (1/6) of the infected mice; however, it was not detected in the liver (0/6) or kidney (0/6). In IN-inoculated mice, BVDV antigen was detected in the lung and mesenteric lymph nodes of one BVDV-infected mouse but was not detected in other tissues. The results of this study suggest that the spleen is the most reliable tissue for BVDV antigen detection using IHC in the IP-injected group. Our study demonstrates that mice can be infected by BVDV. This is the first report of BVDV infection in mice.


Subject(s)
Diarrhea Virus 1, Bovine Viral/pathogenicity , Diarrhea Virus 2, Bovine Viral/pathogenicity , Pestivirus Infections/virology , Animals , Kidney/pathology , Kidney/virology , Liver/pathology , Liver/virology , Lung/pathology , Lung/virology , Lymphoid Tissue/pathology , Lymphoid Tissue/virology , Mice/virology , Mice, Inbred BALB C , Pestivirus Infections/pathology , Real-Time Polymerase Chain Reaction
17.
Avian Pathol ; 44(3): 175-81, 2015.
Article in English | MEDLINE | ID: mdl-25703639

ABSTRACT

We compared the clinical signs, histopathological lesions and distribution of viral antigens among infected young (meat-type) and older (breeder) ducks that were naturally infected with the highly pathogenic avian influenza (HPAI) virus during the 2010-2011 Korean outbreak. The meat-type ducks had a high mortality rate (30%) and showed severe neurological signs such as head tremors and paresis. In contrast, HPAI-infected breeder ducks had minimal clinical signs but a decreased egg production rate. The histopathological characteristics of infected meat-type ducks included necrotic lesions of heart and brain, which may have primarily contributed to the high mortality rate. In contrast, the breeder ducks only presented necrotic splenitis, and viral antigens were only detected in the trachea, lungs and spleen. Younger ducks had a high viral titre in the organs, high levels of viral shedding and a high mortality rate after experimental HPAI virus infection. Compared to the breeder ducks, the meat-type ducks were raised in smaller farms that had poor quarantine and breeding facilities. It is therefore possible that better biosecurity in the breeder farms could have reduced the infection dose and subsequently the severity of the disease. Thus, age and management may be the influencing factors for HPAI susceptibility in ducks.


Subject(s)
Disease Outbreaks/veterinary , Ducks , Influenza A Virus, H5N1 Subtype , Influenza in Birds/epidemiology , Influenza in Birds/pathology , Poultry Diseases/epidemiology , Poultry Diseases/virology , Age Factors , Animals , Antigens, Viral/metabolism , Brain/pathology , Histological Techniques , Immunohistochemistry , Myocardium/pathology , Poultry Diseases/pathology , Republic of Korea/epidemiology
18.
Appl Opt ; 54(2): 189-94, 2015 Jan 10.
Article in English | MEDLINE | ID: mdl-25967616

ABSTRACT

We report the observation of transverse mode instability (TMI) in a pulsed single-frequency ytterbium-doped large-core fiber amplifier in which stimulated Brillouin scattering (SBS) is generated easily owing to the high peak power and narrow linewidth of the laser pulses. It was shown experimentally that the threshold of TMI is almost the same as that of SBS and that the suppression of SBS also increases the threshold of TMI, which indicates that the TMI originates from SBS in the fiber.

19.
Sensors (Basel) ; 15(7): 17397-419, 2015 Jul 17.
Article in English | MEDLINE | ID: mdl-26193281

ABSTRACT

To monitor large areas or simultaneously measure multiple points, multiple unmanned aerial vehicles (UAVs) must be flown in formation. To perform such flights, sensor information generated by each UAV should be shared via communications. Although a variety of studies have focused on the algorithms for formation flight, these studies have mainly demonstrated the performance of formation flight using numerical simulations or ground robots, which do not reflect the dynamic characteristics of UAVs. In this study, an onboard sensor information sharing system and formation flight algorithms for multiple UAVs are proposed. The communication delays of radiofrequency (RF) telemetry are analyzed to enable the implementation of the onboard sensor information sharing system. Using the sensor information sharing, the formation guidance law for multiple UAVs, which includes both a circular and close formation, is designed. The hardware system, which includes avionics and an airframe, is constructed for the proposed multi-UAV platform. A numerical simulation is performed to demonstrate the performance of the formation flight guidance and control system for multiple UAVs. Finally, a flight test is conducted to verify the proposed algorithm for the multi-UAV system.

20.
Percept Mot Skills ; 118(2): 491-506, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24897882

ABSTRACT

Although the behavioral characteristics and the neural correlates of prism adaptation processes have been studied extensively, the underlying mechanism is yet to be investigated. Recently, somatosensory suppression was heralded as a mechanism for the sensory re-alignment process accompanying the adaptation. Somatosensory suppression should facilitate the re-alignment process in the proprioceptive system. The shift in the proprioceptive system takes place mostly during a concurrent visual feedback (CVF) condition; during a terminal visual feedback (TVF) condition, the visual system experiences significant adaptation (visual shift), so somatosensory suppression should have minimal functional consequences under TVF. To test this hypothesis, a repetitive transcranial magnetic stimulation (rTMS) was applied to the primary somatosensory cortex as an artificial somatosensory suppression right after the reaching initiation in CVF and TVF conditions, and changes in adaptation were observed. Because somatosensory suppression is already in effect during CVF, rTMS would cause no significant changes. During TVF with rTMS, however, significantly different patterns of adaptation could be expected when compared to a sham rTMS condition. Young adults (N = 12) participated in 4 sessions (CVF/ TVF, real/sham rTMS); visual proprioceptive, and total shifts were measured. Movement time and curvature of the reaching movement were measured during the adaptation phase. Results showed that while the total shift was unchanged, the proprioceptive shift increased and the visual shift decreased in the TVF condition when rTMS was delivered. However, the total, proprioceptive, and visual shifts were not influenced by rTMS in the CVF condition. Suppression of proprioception induced by the rTMS could be one of the requisites for successful proprioceptive shift during prism adaptation.


Subject(s)
Adaptation, Physiological/physiology , Feedback, Sensory/physiology , Proprioception/physiology , Psychomotor Performance/physiology , Visual Perception/physiology , Adult , Humans , Somatosensory Cortex , Transcranial Magnetic Stimulation , Young Adult
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