scholarly journals Energy-Constrained Design of Joint NOMA-Diversity Schemes with Imperfect Interference Cancellation

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4194
Author(s):  
Fulvio Babich ◽  
Giulia Buttazzoni ◽  
Francesca Vatta ◽  
Massimiliano Comisso

This study proposes a set of novel random access protocols combining Packet Repetition (PR) schemes, such as Contention Resolution Diversity Slotted Aloha (CRDSA) and Irregular Repetition SA (IRSA), with Non Orthogonal Multiple Access (NOMA). Differently from previous NOMA/CRDSA and NOMA/IRSA proposals, this work analytically derives the energy levels considering two realistic elements: the residual interference due to imperfect Interference Cancellation (IC), and the presence of requirements on the power spent for the transmission. More precisely, the energy-limited scenario is based on the relationship between the average available energy and the selected code modulation pair, thus being of specific interest for the implementation of the Internet of Things (IoT) technology in forthcoming fifth-generation (5G) systems. Moreover, a theoretical model based on the density evolution method is developed and numerically validated by extensive simulations to evaluate the limiting throughput and to explore the actual performance of different NOMA/PR schemes in energy-constrained scenarios.

Author(s):  
Donghui Zhang ◽  
Ruijie Liu

Abstract Orienteering has gradually changed from a professional sport to a civilian sport. Especially in recent years, orienteering has been widely popularized. Many colleges and universities in China have also set up this course. With the improvement of people’s living conditions, orienteering has really become a leisure sport in modern people’s life. The reduced difficulty of sports enables more people to participate, but it also exposes a series of problems. As the existing positioning technology is relatively backward, the progress in personnel tracking, emergency services, and other aspects is slow. To solve these problems, a new intelligent orienteering application system is developed based on the Internet of things. ZigBee network architecture is adopted in the system. ZigBee is the mainstream scheme in the current wireless sensor network technology, which has many advantages such as convenient carrying, low power consumption, and signal stability. Due to the complex communication environment in mobile signal, the collected information is processed by signal amplification and signal anti-interference technology. By adding anti-interference devices, video isolators and other devices, the signal is guaranteed to the maximum extent. In order to verify the actual effect of this system, through a number of experimental studies including the relationship between error and traffic radius and the relationship between coverage and the number of anchor nodes, the data shows that the scheme studied in this paper has a greater improvement in comprehensive performance than the traditional scheme, significantly improving the accuracy and coverage. Especially the coverage is close to 100% in the simulation experiment. This research has achieved good results and can be widely used in orienteering training and competition.


Author(s):  
Tian Wu ◽  
Danyan Hu ◽  
Qingfen Wang

Abstract Background Noni (Morinda citrifolia Linn.) is a tropical tree that bears climacteric fruit. Previous observations and research have shown that the second day (2 d) after harvest is the most important demarcation point when the fruit has the same appearance as the freshly picked fruit (0 d); however, they are beginning to become water spot appearance. We performed a conjoint analysis of metabolome and transcriptome data for noni fruit of 0 d and 2 d to reveal what happened to the fruit at the molecular level. Genes and metabolites were annotated to KEGG pathways and the co-annotated KEGG pathways were used as a statistical analysis. Results We found 25 pathways that were significantly altered at both metabolic and transcriptional levels, including a total of 285 differentially expressed genes (DEGs) and 11 differential metabolites through an integrative analysis of transcriptomics and metabolomics. The energy metabolism and pathways originating from phenylalanine were disturbed the most. The upregulated resistance metabolites and genes implied the increase of resistance and energy consumption in the postharvest noni fruit. Most genes involved in glycolysis were downregulated, further limiting the available energy. This lack of energy led noni fruit to water spot appearance, a prelude to softening. The metabolites and genes related to the resistance and energy interacted and restricted each other to keep noni fruit seemingly hard within two days after harvest, but actually the softening was already unstoppable. Conclusions This study provides a new insight into the relationship between the metabolites and genes of noni fruit, as well as a foundation for further clarification of the post-ripening mechanism in noni fruit.


2019 ◽  
Vol 91 ◽  
pp. 05006
Author(s):  
Rami Qaoud ◽  
Alkama Djamal

The urban fabric of the desert cities is based on the principle of reducing the impact of urban canyons on direct solar radiation. Here comes this research, which is based on a comparative study of the periods of direct solarisation and values of the solar energy of urban canyons via two urban fabrics that have different building densities, where the ratio between L/W is different. In order to obtain the real values of the solar energy (thermal, lighting), the test field was examined every two hours, each three consecutive days. The measurement stations are positioned by the three types of the relationship between L/W, (L≥2w, L=w, L≤0.5w). According to the results, we noticed and recorded the difference in the periods of direct solarization between the types of urban engineering canyons, reaching 6 hours a day, the difference in thermal values of air, reaching 4 °C, and the difference in periods of direct natural lighting, reaching 6 hours. It should be noted that the role of the relationship between L/W is to protect the urban canyons by reducing the impact of direct solar radiation on urban canyons, providing longer hours of shading, and reducing solar energy levels (thermal, lighting) at the urban canyons. This research is classified under the research axis (the studies of external spaces in the urban environment according to the bioclimatic approach and geographic approach). But this research aims to focus on the tracking and studying the distribution of the solar radiation - thermal radiation and lighting radiation - in different types of street canyons by comparing the study of the direct solarization periods of each type and the quantity of solar energy collected during the solarization periods.


2014 ◽  
Vol 42 (2) ◽  
pp. 321-330 ◽  
Author(s):  
YaPing Chang ◽  
XueBing Dong ◽  
Wei Sun

We studied the mechanism of the influence of the Internet of Things (IOT) product characteristics on consumer purchase intention. The results of a survey of 360 consumers showed that 6 dimensions of IOT product characteristics influence purchase intention; namely connectivity, interactivity, telepresence, intelligence, convenience, and security. We found that customer experience was the key mediating variable in the relationship between IOT product characteristics and purchase intention. Connectivity, interactivity, telepresence, intelligence, convenience, and security all positively influenced purchase intention via functional experience. Furthermore, connectivity, telepresence, convenience, and security positively influenced purchase intention via emotional experience. Our findings in the study provide some points of reference for improvement of IOT product design.


2013 ◽  
Vol 31 (11) ◽  
pp. 2387-2396 ◽  
Author(s):  
Chongbin Xu ◽  
Li Ping ◽  
Peng Wang ◽  
Sammy Chan ◽  
Xiaokang Lin

Author(s):  
Nor Fazila Abd Malek ◽  
Nur Ikhwan Mohamad ◽  
Mohansundar Sankaravel2 ◽  
Sakinah Mohd Hassan

Repeated sprint ability (RSA) is typically used for speed-endurance and agility-endurance training and assessment. RSA is preferred as it mimics actual performance during competition. RSA test involves straight sprint and quick turning movements. Thus, the aim of this study is to determine the relationship between height and body weight measurements on RSA performance, as height and weight may influence the mechanical properties of it. Ten male rugby players (body weight 72.99 ± 14.29 kg, height 169 ± 5.55 cm) selected for Perak SUKMA 2018 team were assessed during centralized training ~9 months prior to their competition.  Body weight and height were measured using standard laboratory weight and height scales prior to the RSA test. RSA were hand-timed for 5 repetitions x 2 sets x 60 seconds rest in between repetitions x 5 minutes rest in-between set. The sprints were performed in the evenings, on grass surface with participants wearing full playing attire. Standardized pre-game warm-up and cooling down were performed. Data recorded was analyzed statistically using a t-test comparison for set one versus set two performances. Pearson correlation coefficient was used to analyze the relationship between anthropometric measures and the RSA test. RSA performance has a negative correlation with the athletes’ height (r= -0.233 set 1, r = -0.435 set 2) and body weight (r= -0.556 set 1, r= -0.629 set 2). RSA performance was significantly different between set 1 and set 2 (p=0.001), with set 1 performance better than set 2. Body height and body weight did not influence RSA performance. Athletes involved did not have adequate speed-agility-endurance needed. In practical, selecting athletes based on their body height and body weight with the assumption that taller and heavier athletes may perform better may not be suitable for this kind of sport. On the other hand, using RSA to test and develop the speed-agility-endurance ability for rugby players is suggested.  


Sign in / Sign up

Export Citation Format

Share Document