• Title/Summary/Keyword: Li-Fi

Search Result 39, Processing Time 0.023 seconds

Deep Recurrent Neural Network for Multiple Time Slot Frequency Spectrum Predictions of Cognitive Radio

  • Tang, Zhi-ling;Li, Si-min
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.11 no.6
    • /
    • pp.3029-3045
    • /
    • 2017
  • The main processes of a cognitive radio system include spectrum sensing, spectrum decision, spectrum sharing, and spectrum conversion. Experimental results show that these stages introduce a time delay that affects the spectrum sensing accuracy, reducing its efficiency. To reduce the time delay, the frequency spectrum prediction was proposed to alleviate the burden on the spectrum sensing. In this paper, the deep recurrent neural network (DRNN) was proposed to predict the spectrum of multiple time slots, since the existing methods only predict the spectrum of one time slot. The continuous state of a channel is divided into a many time slots, forming a time series of the channel state. Since there are more hidden layers in the DRNN than in the RNN, the DRNN has fading memory in its bottom layer as well as in the past input. In addition, the extended Kalman filter was used to train the DRNN, which overcomes the problem of slow convergence and the vanishing gradient of the gradient descent method. The spectrum prediction based on the DRNN was verified with a WiFi signal, and the error of the prediction was analyzed. The simulation results proved that the multiple slot spectrum prediction improved the spectrum efficiency and reduced the energy consumption of spectrum sensing.

A Hybrid of Smartphone Camera and Basestation Wide-area Indoor Positioning Method

  • Jiao, Jichao;Deng, Zhongliang;Xu, Lianming;Li, Fei
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.10 no.2
    • /
    • pp.723-743
    • /
    • 2016
  • Indoor positioning is considered an enabler for a variety of applications, the demand for an indoor positioning service has also been accelerated. That is because that people spend most of their time indoor environment. Meanwhile, the smartphone integrated powerful camera is an efficient platform for navigation and positioning. However, for high accuracy indoor positioning by using a smartphone, there are two constraints that includes: (1) limited computational and memory resources of smartphone; (2) users' moving in large buildings. To address those issues, this paper uses the TC-OFDM for calculating the coarse positioning information includes horizontal and altitude information for assisting smartphone camera-based positioning. Moreover, a unified representation model of image features under variety of scenarios whose name is FAST-SURF is established for computing the fine location. Finally, an optimization marginalized particle filter is proposed for fusing the positioning information from TC-OFDM and images. The experimental result shows that the wide location detection accuracy is 0.823 m (1σ) at horizontal and 0.5 m at vertical. Comparing to the WiFi-based and ibeacon-based positioning methods, our method is powerful while being easy to be deployed and optimized.

Power Allocation Method of Downlink Non-orthogonal Multiple Access System Based on α Fair Utility Function

  • Li, Jianpo;Wang, Qiwei
    • Journal of Information Processing Systems
    • /
    • v.17 no.2
    • /
    • pp.306-317
    • /
    • 2021
  • The unbalance between system ergodic sum rate and high fairness is one of the key issues affecting the performance of non-orthogonal multiple access (NOMA) system. To solve the problem, this paper proposes a power allocation algorithm to realize the ergodic sum rate maximization of NOMA system. The scheme is mainly achieved by the construction algorithm of fair model based on α fair utility function and the optimal solution algorithm based on the interior point method of penalty function. Aiming at the construction of fair model, the fair target is added to the traditional power allocation model to set the reasonable target function. Simultaneously, the problem of ergodic sum rate and fairness in power allocation is weighed by adjusting the value of α. Aiming at the optimal solution algorithm, the interior point method of penalty function is used to transform the fair objective function with unequal constraints into the unconstrained problem in the feasible domain. Then the optimal solution of the original constrained optimization problem is gradually approximated within the feasible domain. The simulation results show that, compared with NOMA and time division multiple address (TDMA) schemes, the proposed method has larger ergodic sum rate and lower Fairness Index (FI) values.

Effects of Curcumin on the Pharmacokinetics of Loratadine in Rats: Possible Role of CYP3A4 and P-glycoprotein Inhibition by Curcumin

  • Li, Cheng;Choi, Byung-Chul;Kim, Dong-Ki;Choi, Jun-Shik
    • Biomolecules & Therapeutics
    • /
    • v.19 no.3
    • /
    • pp.364-370
    • /
    • 2011
  • The purpose of this study was to investigate the effects of curcumin on the pharmacokinetics of loratadine in rats. The effect of curcumin on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity was evaluated. Pharmacokinetic parameters of loratadine were also determined after oral and intravenous administration in the presence or absence of curcumin. Curcumin inhibited CYP3A4 activity with an IC50 value of 2.71 ${\mu}M$ and the relative cellular uptake of rhodamine-123 was comparable. Compared to the oral control group, curcumin significantly increased the area under the plasma concentration-time curve and the peak plasma concentration by 39.4-66.7% and 34.2-61.5%. Curcumin also significantly increased the absolute bioavailability of loratadine by 40.0-66.1% compared to the oral control group. Consequently, the relative bioavailability of loratadine was increased by 1.39- to 1.67-fold. In contrast, curcumin had no effect on any pharmacokinetic parameters of loratadine given intravenously, implying that the enhanced oral bioavailability may be mainly due to increased intestinal absorption caused via P-gp and CYP3A4 inhibition by curcumin rather than to reduced renal and hepatic elimination of loratadine. Curcumin enhanced the oral bioavailability of loratadine in this study. The enhanced bioavailability of loratadine might be mainly attributed to enhanced absorption in the gastrointestinal tract via the inhibition of P-gp and reduced fi rst-pass metabolism of loratadine via the inhibition of the CYP3A subfamily in the small intestine and/or in the liver by curcumin.

Effects of Immune Stress on Performance Parameters, Intestinal Enzyme Activity and mRNA Expression of Intestinal Transporters in Broiler Chickens

  • Feng, Y.;Yang, X.J.;Wang, Y.B.;Li, W.L.;Liu, Y.;Yin, R.Q.;Yao, J.H.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.25 no.5
    • /
    • pp.701-707
    • /
    • 2012
  • Immune stress is the loss of immune homeostasis caused by external forces. The purpose of this experiment was to investigate the effects of immune stress on the growth performance, small intestinal enzymes and peristalsis rate, and mRNA expression of nutrient transporters in broiler chickens. Four hundred and thirty-two 1-d-old broilers (Cobb500) were randomly assigned to four groups for treatment; each group included nine cages with 12 birds per cage. Group 1 = no vaccine (NV); Group 2 = conventional vaccine (CV); group 3 = lipopolysaccharide (LPS)+conventional vaccine (LPS); group 4 = cyclophosphamide (CYP)+conventional vaccine (CYP). The results demonstrated that immune stress by LPS and CYP reduced body weight gain (BWG), feed intake (FI), small intestine peristalsis rate and sIgA content in small intestinal digesta (p<0.05). However, the feed conversion ratio (FCR) remained unchanged during the feeding period. LPS and CYP increased intestinal enzyme activity, relative expression of SGLT-1, CaBP-D28k and L-FABP mRNAs (p<0.05). LPS and CYP injection had a negative effect on the growth performance of healthy broiler chickens. The present study demonstrated that NV and CV could improve growth performance while enzyme activity in small intestine and relative expression of nutrient transporter mRNA of NV and CV were decreased in the conditions of a controlled rational feeding environment. It is generally recommended that broilers only need to be vaccinated for the diseases to which they might be exposed.

The Artistic Characteristics of Afrofuturism -Focusing On The Costume Design in Black Panther- (아프로 퓨쳐리즘의 예술적 특성 -영화 블랙팬서 주인공들의 코스튬을 중심으로-)

  • Li, Qi;Kim, Hyun-Joo;Youn, Ji-Young
    • Journal of Digital Convergence
    • /
    • v.18 no.5
    • /
    • pp.433-440
    • /
    • 2020
  • Afrofuturism was born under the combination of the elements of African culture, sci-fi novels, history, afrocentrism and Magic Realism. The aim of this study is to sort out the concepts and characteristics of Afrofuturism basing on the artistic elements appearing in Black Panther. The method is to investigate the academic papers, periodicals, singles and the Internet research related to African culture, Afrofuturism and American superheroes first. And then make the analyzation of the design of uniforms of the major characters in the movie as cases. The result is : First, the resistance of art for social minorities, second, the establishment of identity of black art through the reactionary effect of culture, and third, the artistic healing through SF fantasy.

Antithrombin-III as an early prognostic factor in children with acute lung injury (급성 폐손상 소아 환자에서 조기 예후 인자로서의 antithrombin-III)

  • Lee, Young Seung;Kim, Seonguk;Kang, Eun Kyeong;Park, June Dong
    • Clinical and Experimental Pediatrics
    • /
    • v.50 no.5
    • /
    • pp.443-448
    • /
    • 2007
  • Purpose : To evaluate the potential prognostic value of the antithrombin-III (AT-III) level in the children with acute lung injury (ALI), we analyzed several early predictive factors of death including AT-III level at the onset of ALI and compared the relative risk of them for mortality. Methods : Over a 18-month period, a total of 198 children were admitted to our pediatric intensive care unit and 21 mechanically ventilated patients met ALI criteria, as defined by American-European consensus conference, i.e., bilateral pulmonary infiltrates and $PaO_2/FiO_2$ lower than 300 without left atrial hypertension. Demographic variables, hemodynamic and respiratory parameters, underlying diseases, as well as Pediatric Risk of Mortality-III (PRISM-III) scores and Lung Injury Score (LIS) at admission were collected. AT-III levels were measured within 3 hours after admission. These variables were compared between survivors and non-survivors and entered into a multiple logistic regression analysis to evaluate their independent prognostic roles. Results : The overall mortality rate was 38.1% (8/21). Non-survivors showed lower age, lower lung compliance, higher PEEP, higher oxygenation index (OI), lower arterial pH, lower $PaO_2/FiO_2$, higher PRISM-III score and LIS, and lower AT-III level. PRISM-III score, LIS, OI and decreased AT-III level (less than 70%) were independently associated with a risk of death and the odds ratio of decreased AT-III level for mortality is 2.75 (95% confidence interval; 1.28-4.12) Conclusion : These results suggest that the decreased level of AT-III is an important prognostic factor in children with ALI and the replacement of AT-III may be considered as an early therapeutic trial.

Intestinal segment and vitamin D3 concentration affect gene expression levels of calcium and phosphorus transporters in broiler chickens

  • Jincheng Han;Lihua Wu;Xianliang Lv;Mengyuan Liu;Yan Zhang;Lei He;Junfang Hao;Li Xi;Hongxia Qu;Chuanxin Shi;Zhiqiang Li;Zhixiang Wang;Fei Tang;Yingying Qiao
    • Journal of Animal Science and Technology
    • /
    • v.65 no.2
    • /
    • pp.336-350
    • /
    • 2023
  • Two experiments were conducted in this research. Experiment 1 investigated the spatial expression characteristics of calcium (Ca) and phosphorus (P) transporters in the duodenum, jejunum, and ileum of 21-day-old broilers provided with adequate nutrient feed. Experiment 2 evaluated the effects of dietary vitamin D3 (VD3) concentration (0, 125, 250, 500, 1,000, and 2,000 IU/kg) on growth performance, bone development, and gene expression levels of intestinal Ca and P transporters in 1-21-day-old broilers provided with the negative control diet without supplemental VD3. Results in experiment 1 showed that the mRNA levels of calcium-binding protein 28-kDa (CaBP-D28k), sodium-calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1b (PMCA1b), and IIb sodium-phosphate cotransporter (NaPi-IIb) were the highest in the broiler duodenum. By contrast, the mRNA levels of inorganic phosphate transporter 1 (PiT-1) and 2 (PiT-2) were the highest in the ileum. Results in experiment 2 showed that adding 125 IU/kg VD3 increased body weight gain (BWG), feed intake (FI), bone weight, and percentage and weight of Ca and P in the tibia and femur of 1-21-day-old broilers compared with the negative control diet (p < 0.05). The rise in dietary VD3 levels from 125 to 1,000 IU/kg further increased the BWG, FI, and weights of the bone, ash, Ca, and P (p < 0.05). No difference in growth rate and leg bone quality was noted in the broilers provided with 1,000 and 2,000 IU/kg VD3 (p > 0.05). Supplementation with 125-2,000 IU/kg VD3 increased the mRNA abundances of intestinal Ca and P transporters to varying degrees. The mRNA level of CaBP-D28k increased by 536, 1,161, and 28 folds in the duodenum, jejunum, and ileum, respectively, after adding 1,000 IU/kg VD3. The mRNA levels of other Ca and P transporters (PMCA1b, NCX1, NaPi-IIb, PiT-1, and PiT-2) increased by 0.57-1.74 folds by adding 1,000-2,000 IU/kg VD3. These data suggest that intestinal Ca and P transporters are mainly expressed in the duodenum of broilers. Moreover, the addition of VD3 stimulates the two mineral transporter transcription in broiler intestines.

Influence of Lighting Schedule and Nutrient Density in Broiler Chickens: Effect on Growth Performance, Carcass Traits and Meat Quality

  • Li, Wen-Bin;Guo, Yan-Li;Chen, Ji-Lan;Wang, Rong;He, Yao;Su, Dong-Ge
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.23 no.11
    • /
    • pp.1510-1518
    • /
    • 2010
  • The study was conducted to evaluate the effect of lighting schedule and nutrient density on growth performance, carcass traits and meat quality of broiler chickens. A total of 576 day old Arbor Acre male chickens was used with a $4{\times}2$ factorial arrangement. The four lighting schedules were continuous (23 L:1 D, CL), 20 L:4 D (12 L:2 D:8 L:2 D), 16 L:8 D (12 L:3 D:2 L:3 D: 2 L:2 D) and 12 L:12 D (9 L:3 D:1 L:3 D:1 L:3 D:1 L:3 D) and provided by incandescent bulbs. The two nutrient densities were high (H, starter diet: 13.39 MJ/kg apparent metabolisable energy (AME), 23.00% crude protein (CP); finisher diet: 13.39 MJ AME/kg, 19.70% CP) and low energy and protein level (L, starter diet: 12.03 MJ AME/kg, 20.80% CP; finisher diet: 12.14 MJ AME/kg, 18.30% CP). Houses with dark curtains and solid sidewalls were used. Chickens were randomly allocated to the 8 treatments with each treatment comprising 6 replicates of 12 chickens. Feed and water were available ad libitum. Lighting schedules showed no difference (p>0.05) in growth performance at the end of the experiment. 12 L:12 D significantly reduced (p<0.05) the concentration of malondialdehyde (MDA) compared to 23 L:1 D treatment. Intermittent lighting (IL) schedules produced higher protein content (p<0.001) in breast meat. Birds on high density diets had higher body weight (BW), feed intake (FI) (p<0.001), and feed conversion ratio (FCR) (p<0.001) throughout the experiment with the exception of 36 to 42 d. High nutrient density increased (p<0.05) abdominal fat, decreased (p<0.05) the moisture loss of meat, and reduced percentage of wings and legs. There was a significant lighting schedule${\times}$diet interaction (p<0.001) on FCR for days 8 to 14 and 15 to 21. Results indicated that IL can give similar growth performance in comparison with CL, meanwhile with positive effects on meat quality by increasing protein content and decreasing the concentration of MDA. High nutrient density resulted in greater growth performance.