2,534 research outputs found
Interaction-aware Kalman Neural Networks for Trajectory Prediction
Forecasting the motion of surrounding obstacles (vehicles, bicycles,
pedestrians and etc.) benefits the on-road motion planning for intelligent and
autonomous vehicles. Complex scenes always yield great challenges in modeling
the patterns of surrounding traffic. For example, one main challenge comes from
the intractable interaction effects in a complex traffic system. In this paper,
we propose a multi-layer architecture Interaction-aware Kalman Neural Networks
(IaKNN) which involves an interaction layer for resolving high-dimensional
traffic environmental observations as interaction-aware accelerations, a motion
layer for transforming the accelerations to interaction aware trajectories, and
a filter layer for estimating future trajectories with a Kalman filter network.
Attributed to the multiple traffic data sources, our end-to-end trainable
approach technically fuses dynamic and interaction-aware trajectories boosting
the prediction performance. Experiments on the NGSIM dataset demonstrate that
IaKNN outperforms the state-of-the-art methods in terms of effectiveness for
traffic trajectory prediction.Comment: 8 pages, 4 figures, Accepted for IEEE Intelligent Vehicles Symposium
(IV) 202
Complication and Contraindication of Full Endoscopic Lumbar Decompression
By reviewing various literatures on endoscopic surgery for lumbar spinal stenosis and systematically analyzing the contraindications and complications of endoscopic surgery, the purpose of this study is to distinguish appropriate indications and contraindications for endoscopic surgery, and to predict the prognosis for the incidence of complications. We searched the PubMed databases to identify articles on endoscopic surgery for lumbar spinal stenosis. Preoperative exclusion criteria were included in contraindication, and complications that occurred during and after surgery were included. We analyzed clinical outcomes and classified the prescribed contraindication and complications according to the paper. We identified 120 articles, and 48 met our criteria, with evidence ranging from level I to level IV. After reviewing the literature, the analysis result, Contraindication of full endoscopic lumbar decompression are spondylolisthesis (>grade 2), instability, previous surgery, tumor (metastasis), infection, scoliosis, mainly back pain, painless weakness, cauda equine syndrome, etc. Complications of full endoscopic lumbar decompression are dura tearing, epidural hematoma, transient dysesthesia, untreated pain, motor weakness, cauda equine syndrome, incomplete decompression, etc. Fully endoscopic lumbar decompression is a safe, effective option for treating lumbar spinal stenosis, owever, it is important to select the surgical indication well, and various complications may occur after surgery
Properties of the Planetary Caustic Perturbation
Just two of 10 extrasolar planets found by microlensing have been detected by
the planetary caustic despite the higher probability of planet detection
relative to the central caustic which has been responsible for four extrasolar
planet detections. This is because the perturbations induced by the planetary
caustic are unpredictable, thus making it difficult to carry out strategic
observations. However, if future high-cadence monitoring surveys are conducted,
the majority of planetary caustic events including the events by free-floating
planets and wide-separation planets would be detected. Hence, understanding the
planetary caustic perturbations becomes important. In this paper, we
investigate in detail the pattern of the planetary caustic perturbations. From
this study, we find three properties of the planetary caustic perturbations.
First, planetary systems with the same star-planet separation (s) basically
produce perturbations of constant strength regardless of the planet/star mass
ratio (q), but the duration of each perturbation scales with sqrt{q}. Second,
close planetary systems with the same separation produce essentially the same
negative perturbations between two triangular-shaped caustics regardless of q,
but the duration of the perturbations scales with sqrt{q}. Third, the positive
perturbations for planetary systems with the same mass ratio become stronger as
the caustic shrinks with the increasing |log s|, while the negative
perturbations become weaker. We estimate the degeneracy in the determination of
q that occurs in planetary caustic events. From this, we find that the mass
ratio can be more precisely determined as q increases and |log s| decreases. We
also find that the degeneracy range of events for which the source star passes
close to the planetary caustic is usually very narrow, and thus it would not
significantly affect the determination of q.Comment: 5 pages, 3 figures, 2 tables, accepted in MNRA
Recommended from our members
Association between shift work and obesity among female nurses: Korean Nurses’ Survey
Background: Shift work has been hypothesized as a risk factor for obesity. In this study, we investigated the association between current shift work and body mass index (BMI) among female nurses in Korea. The relationship between duration of shift work and BMI of the participants was also evaluated. Methods: This cross-sectional survey evaluated participants in the Korean Nurses’ Survey, conducted from October to December 2011, using web-based self-administered questionnaires. A total of 9,989 nurses were included among 10,000 who registered on the survey web site (5,287 shift workers and 4,702 non-shift workers). Current shift workers were divided into tertiles of shift work duration (0.08–3.00 years, n = 1,732; 3.08–6.75 years, n = 1,731; and 6.83–38.00 years, n = 1,686). The BMI thresholds of overweight and obesity were ≥23 kg/m2 and ≥25 kg/m2, respectively. Data were analyzed using SPSS software. Results: Mean participant age was 33.2 ± 8.6 years and the mean BMI was 20.9 ± 2.5 kg/m2. There were statistically significant differences in current smoking status, regular drinking habit, dietary habits, regular exercise, sleep problems and self-perceived health status according to duration of shift work. The overall prevalence of overweight/obesity (18.6%) and obesity (7.4%) increased significantly as shift work duration increased from the lowest to highest tertile (P for trend <0.001). Multivariate logistic regression analysis revealed no association between current shift work and BMI. However, after adjusting for potential confounders, the participants with the longest duration of shift work were 1.63 (95% CI, 1.22–2.17) times more likely to be overweight or obese than those with the shortest duration. There was a significant positive association between obesity and shift work duration in the unadjusted analysis; however, it was attenuated and no longer significant in the multivariate model. Conclusions: The duration of shift work was positively associated with prevalence of overweight/obesity in nurses in Korea. Although these findings need to be confirmed in prospective studies, they suggest that special attention should be paid to female nurses with a long duration of shift work
High-speed infrared phase modulators using short helical pitch ferroelectric liquid crystals
A fast phase modulator based on ferroelectric liquid crystal (FLC) is demonstrated and its performances characterized. For uniform alignment and pure phase modulation, we propose a new FLC device configuration using short helical pitch material and homeotropic alignment structure. This device is driven by periodic in-plane electrode stripes implemented on the surface of both cell substrates. As a result, we have obtained large phase modulation ( \u3e 2 pi at lambda=1.55 mu m) and fast response ( \u3c 200 mu sec)
Development of an Evaluation Methodology for Loss of Large Area induced from Extreme Events with malicious origin
Event of loss of large area (LOLA) induced from extreme external event at multi-units
nuclear installation has been emerged a new challenges in the realm of nuclear safety and regulation
after Fukushima Dai-Ichi accident. The relevant information and experience on evaluation
methodology and regulatory requirements are rarely available and negative to share due to the
security sensitivity. Most of countries has been prepared their own regulatory requirements and
methodologies to evaluate impact of LOLA at nuclear power plant. In Korea, newly amended the
Nuclear Safety Acts requires to assess LOLA in terms of EDMG (Extended Damage Mitigation
Guideline). Korea Institute of Nuclear Safety (KINS) has performed a pilot research project to
develop the methodology and regulatory review guidance on LOLA at multi-units nuclear power
plant since 2014. Through this research, we proposed a methodology to identify the strategies for
preventive and mitigation of the consequences of LOLA utilizing PSA techniques or its results. The
proposed methodology is comprised of 8 steps including policy consideration, threat evaluation,
identification of damage path sets, SSCs capacity evaluation and identification of mitigation
measures and strategies. The consequence of LOLA due to malevolent aircraft crash may
significantly susceptible with analysis assumptions including type of aircraft, amount of residual
fuel, and hittable angle and so on, which cannot be shared overtly. This paper introduces a
evaluation methodology for LOLA using PSA technique and its results. Also we provide a case
study to evaluate hittable access angle using flight simulator for two types of aircrafts and to
identify potential path sets leading to core damage by affected SSCs within damaged area
The Korean urban rural elderly cohort study: study design and protocol
BACKGROUND: Korea is one of the fastest aging countries and is expected to become a super-aged society within 12 years. The Korean Urban Rural Elderly (KURE) study was developed to evaluate the epidemiological characteristics and establish the prevention and management of major disorders of the elderly in Korea. METHODS/DESIGN: The KURE study is a community-based prospective cohort study on health, aging, and common geriatric disorders of Korean elderly persons aged at least 65 years. To construct a cohort reflecting both urban and rural areas, we selected 2 representative communities in the country. To establish multidisciplinary approaches to geriatric health, this study was performed by researchers in the divisions of geriatrics, preventive medicine, endocrinology, and sociology. The baseline examinations began in 2012; the study will follow more than 4,000 elderly Koreans over 10 years. The first and second follow-up health examinations will be performed every 4 years. Every 2 years after each health examination, inter-assessment interview will be conducted to improve participant retention. DISCUSSION: The KURE study will provide longitudinal epidemiologic data on health, aging, and common geriatric disorders of the elderly in Korea. This is a comprehensive, multidisciplinary study of the elderly with respect to biological, physical, socio-economic, and environmental factors. The results of this study will contribute to improve public health and welfare policies for the aging society in Korea
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