scholarly journals Social-Aware Caching Strategy Based on Joint Action Deep Reinforcement Learning

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jing Yang ◽  
Zhuowei Song ◽  
Peng He ◽  
Yaping Cui ◽  
Dapeng Wu ◽  
...  
Keyword(s):  
Joint Action ◽  
Base Station ◽  
Domain Model ◽  
Three Dimensions ◽  
Physical Domain ◽  
Social Domain ◽  
Caching Strategy ◽  
Communication Links ◽  
Cache Hit Ratio ◽  
Inactive Users

Caching in device-to-device (D2D) networks is emerging a promising trend, which enables to reduce backhaul traffic. Moreover, social interaction among users influences the performance of overall system network. Therefore, it is crucial to consider social attributes in the D2D networks to develop a caching strategy to resolve the problem of unbalanced content distributed. In this paper, we consider two types of users according to their activeness, i.e., active users and inactive users. Inactive users assist active users cache contents during off-peak periods and provide the contents to the active users during peak periods to relieve the pressure of base station (BS). In addition, caching system model is divided into physical domain model and social domain model. In physical domain, the quality of communication links is judged by the delay between D2D users. In social domain, based on a real-world dataset, CiaoDVD, we calculate user similarity in three dimensions and obtain user trust by a trust topology to measure user relationships. Finally, in order to maximize the cache hit ratio, a joint action deep Q -networks (JADQN) framework is proposed to pair the active users with inactive users and distribute the contents to inactive users. Simulation results indicate that the proposed strategy improves the cache hit ratio by 42.9% and reduces the download delay by 48.8% compared with least frequency used (LFU) algorithm, which validates the effectiveness of our method.

scholarly journals IBP Based Caching Strategy in D2D

2019 ◽  
Vol 9 (12) ◽  
pp. 2416 ◽  
Author(s):  
Chun Shan ◽  
Xiao-ping Wu ◽  
Yan Liu ◽  
Jun Cai ◽  
Jian-zhen Luo
Keyword(s):  
Communication Networks ◽  
Network Performance ◽  
Wireless Systems ◽  
Base Station ◽  
D2d Communication ◽  
Social Communities ◽  
Caching Strategy ◽  
Node Importance ◽  
Communication Capacity ◽  
Communication Links

Device to Device (D2D) communication is a key technology in 5th generation wireless systems to increase communication capacity and spectral efficiency. Applying caching into D2D communication networks, the device can retrieve content from other devices by establishing D2D communication links. In this way, the backhaul traffic can be significantly reduced. However, most of the existing caching schemes in D2D are proactive caching, which cannot satisfy the requirement of real-time updating. In this paper, we propose an Indian Buffet Process based D2D caching strategy (IBPSC). Firstly, we construct a geographical D2D communication network to provide high quality D2D communications according to physical closeness between devices. Then devices are divided into several social communities. Devices are ranked by their node importance to community in each community. The base station makes caching decisions for devices according to contrition degree. Experimental results show that IBPSC achieves best network performance.

scholarly journals Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

2021 ◽  
Author(s):  
Pengfei Yi ◽  
Liang Zhu ◽  
Lipeng Zhu ◽  
Zhenyu Xiao
Keyword(s):  
Power Allocation ◽  
Upper Bound ◽  
Three Dimensional ◽  
Geographic Information ◽  
Base Station ◽  
Lagrangian Multipliers ◽  
Loop Optimization ◽  
Convex Problem ◽  
Communication Links ◽  
Minimum Capacity

<div>In this paper, we study to employ geographic information to address the blockage problem of air-to-ground links between UAV and terrestrial nodes. In particular, a UAV relay is deployed to establish communication links from a ground base station to multiple ground users. To improve communication capacity, we fifirst model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information. Then, an optimization problem is formulated to maximize the minimum capacity among users by jointly optimizing the 3-D position and power allocation of the UAV relay, under the constraints of link capacity, maximum transmit power, and blockage. To solve this complex non-convex problem, a two-loop optimization framework is developed based on Lagrangian relaxation. The outer-loop aims to obtain proper Lagrangian multipliers to ensure the solution of the Lagrangian problem converge to the tightest upper bound on the original problem. The inner-loop solves the Lagrangian problem by applying the block coordinate descent (BCD) and successive convex approximation (SCA) techniques, where UAV 3-D positioning and power allocation are alternately optimized in each iteration. Simulation results confifirm that the proposed solution signifificantly outperforms two benchmark schemes and achieves a performance close to the upper bound on the UAV relay system.</div>

GaN based RF Modules - Demands & Needs for Packaging

2011 ◽  
Vol 2011 (1) ◽  
pp. 000896-000899
Author(s):  
M. Oppermann ◽  
K. Widmer ◽  
R. Reber ◽  
H. Sledzik ◽  
P. Schuh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Semiconductor Devices ◽  
Base Station ◽  
Absolute Minimum ◽  
Tests And Measurements ◽  
Gaas Devices ◽  
X Band ◽  
Communication Links ◽  
New Material ◽  
Soldering Technology

GaN/SiC based powerbars and MMICs are the youngest semiconductor devices which have arrived in the field of Radio Frequency modules and applications, e.g. radar, communication links and high power transmitters and amplifiers. Nearly 5 years ago, the first GaN devices were used in the fields of telecommunication equipment, mainly in base-station amplifiers and today GaN devices are more and more part of modern radar applications, like T/R (Transmit/Receive) modules in AESA (Active Electronically Scanned Array) antennas. The main advantages of GaN/SiC semiconductor devices in comparison to GaAs-devices are the higher bandwidth, higher robustness level and the higher operation voltage. Another big issue of GaN is the higher power density, with in minimum 4 times higher values compared to GaAs. Therefore the assembly of GaN MMICs and powerbars on heatsinks and module-baseplates is a big challenge for soldering technology. An absolute minimum of voids between backside of the GaN/SiC devices and the heatsink is necessary to guarantee an optimised heat transfer during operation. Different package materials and technologies are on the market and big international package suppliers deal with new material combinations, like sandwich structures of Cu and Mo. Materials like Al-diamond are used for heatsink materials and with special tests and measurements the results of heat transfer studies will be shown. In this paper examples of power amplifiers, operating in the frequency range of 2–6 GHz and 6–18GHz, and a typical X-Band Frontend will be shown and the RF results will be discussed.

scholarly journals Comparative study on effect of oral hypoglycemics and insulin treatment on quality of life among diabetic subjects

2017 ◽  
Vol 4 (5) ◽  
pp. 1246
Author(s):  
Harish Kumar S. ◽  
Srinivasa S. V. ◽  
Prabhakar K.
Keyword(s):  
Quality Of Life ◽  
Communicable Disease ◽  
Tertiary Care ◽  
Physical Domain ◽  
Tertiary Care Centre ◽  
Social Domain ◽  
Insulin Group ◽  
Oral Hypoglycemics ◽  
Oral Group

Background: Diabetes is a chronic non-communicable disease with variable presentation and complications. It is well known that over a period of time complications sets in and causes substantial decrease in the patient’s quality of life (QoL). QoL domains plays and important factor in prediction of outcome of diabetic treatment. Hence this study was conducted with the objectives to find the difference in quality of life (QoL) domains in diabetics on oral hypoglycaemic agents and Insulin.Methods: Longitudinal Study was undertaken in tertiary care centre, for duration of 6 months. Type 2 Diabetics on treatment with oral hypoglycemics and Insulin were included in the study. Socio - demographic profile, laboratory investigations were collected using structured and pretested questionnaire. Quality of life was assessed by WHOQOL-BREF. SPSS 22 version, EPI Info and Open EPI software were used for Statistical analysis. Chi-square and Students t-test were the statistical tests.Results: 59 diabetic subjects were included in Oral and insulin group respectively. Mean age of oral hypoglycemics was 59.6±8.7 years and Insulin group was 61.4±8.2 years. Age and gender were matched between two groups. Glycemic profile was significantly higher in Oral group than in Insulin group. Physical domain was significantly higher (better) in oral group than in Insulin group. Psychological and Social domain was significantly higher (better) in Insulin group. Hence QoL is affected by type of hypoglycaemic agent used among diabetics.Conclusions: Quality of life with respect to physical domain was reduced in Insulin group, were as psychological and social domain was reduced in Oral group.

scholarly journals Analysis of the Quality of Life of the Elderly in the Village of Bukit Harapan

1970 ◽  
Vol 2 (3) ◽  
pp. 107-116
Author(s):  
Aszrul AB ◽  
Andi Suswani ◽  
Buharman
Keyword(s):  
Quality Of Life ◽  
Cultural Context ◽  
Univariate Analysis ◽  
Sampling Technique ◽  
The Elderly ◽  
Survey Method ◽  
Physical Domain ◽  
Social Domain ◽  
Social Environmental

Quality of life is a person's perception in a cultural context and norms that are relevant to the person's place of life-related to the goals, expectations, standards, and concern for his life. The purpose of this study was to determine the quality of life of the elderly in terms of physical, psychological, level of independence, social, environmental, spiritual life in Bukit Harapan Village in 2018. This study uses a descriptive survey method with a "probability sampling" approach. The sample in this study was 78 respondents with a population of 340 determined using a sampling technique. Data collection was carried out using a questionnaire sheet (check sheet). The analysis used is a univariate analysis which is seen from the results of the frequency distribution. The study showed that the quality of life of the elderly is good as much as 75.3% and the quality of life that is less than good 25.3%. While seen from the physical domain of the good old 70.1% the physical is not good 29.9%. while the good psychology domain elderly 67.6% less good psychological 32.5%. Good independence rate of elderly 71.4% Poor independence rate 28.6%. Elderly good social domain 72.7% good social domain 27.3%. The good old neighborhood domain 67.6% and less good domain 32.5%. Spiritual good 84.4% Spiritual bad 15.7%. In this study it can be concluded that the quality of life of the elderly from the physical domain that has a less good quality is more than the good, while psychological, independence, social, environmental, spiritual elderly have a good category.

scholarly journals A Beam Broadening Method for Phased Arrays in Wireless Communications

2021 ◽  
Author(s):  
Corentin Fonteneau ◽  
Matthieu Crussière ◽  
Bruno Jahan
Keyword(s):  
Antenna Arrays ◽  
Main Idea ◽  
Beam Width ◽  
Base Station ◽  
Phase Shifters ◽  
Large Area ◽  
Steering Angle ◽  
Quadratic Phase ◽  
Communication Links ◽  
Beam Broadening

Abstract 5G and IEEE 802.11ay introduce the use of the millimeter band as one promising solution to provide broadband wireless communication at multi-Gb/s user data rate. Due to the severe path-loss at such frequencies, it is generally assumed that large antenna arrays are used at the base station to steer narrow beams and build highly directionnal communication links towards the terminal points. However, broader and less directional beams are also of high interest in some of the steps involved in the establishment or the maintenance of the communication links. Indeed, search of a large area by narrow beams becomes too time consuming and link outage becomes more critical, thus affecting the latency and the robustness of the communications. A method enabling an adaptation of the beam widths is then worthwhile to consider. In this article, we investigate how narrow beams naturally produced by large antenna arrays can be broadened to adapt the beam width to a desired angular sector. We consider that the multi-antenna processing is performed by phase shifters on the radio-frequency stage since its digital counterpart is hardly feasible in practice at such high frequencies. The main idea of our systematic phase-only beam broadening technique relies on the determination of a quadratic phase excitation law from a desired beam width and steering angle. We first lead a thorough analysis of the radiation behavior regarding the coefficients of such quadratic excitation. We then propose a calculation method for determining the polynomial coefficients as a function of the desired beam width and steering angle. This non-iterative beam broadening method is described for boresight and non-boresight directions and is intended for discrete antenna arrays.

scholarly journals Health Related Quality of Life of Pregnant Women Attending Antenatal Clinic of a Tertiary Level Hospital

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Anisha Deuja ◽  
Radha Paudel
Keyword(s):  
Quality Of Life ◽  
Pregnant Women ◽  
Mode Of Delivery ◽  
Antenatal Clinic ◽  
Physical Domain ◽  
Health Related Quality ◽  
Social Domain ◽  
Related Quality ◽  
Health Related

Background: Pregnancy is a normal process in the female life cycle. The complexity of the changes caused by pregnancy restricted to not only the physical problems, but also psychological and social problems and impact on health related quality of life (HRQOL). The objectives of the study were to assess the HRQOL and find out the associations of HRQOL with socio-demographic and obstetric factors of pregnant women. Methods: A descriptive cross-sectional study design was used among 106 pregnant women. Non-probability purposive sampling technique was used. Data were collected using semi-structured interview schedule that were analyzed by using descriptive statistical methods such as frequency, percentage, mean, standard deviation and inferential statistics as chi-square test. Findings: The study showed that respondent’s level of QoL was highest on psychological domain (96.2%) and the lowest level (14.2%) was found in Physical domain. There was significant association of physical domain in Quality of Life with the age (p=0.003) while type of family, parity, mode of delivery and duration of pregnancy were not associated with physical, psychological and social domain at 0.005 level of significance. Conclusions: Based on the findings, this study concludes that the quality of life of pregnant women in general tends to be good. The physical domain is most affected rather than psychological and social domain. Level of QoL of the pregnant women in Physical domain is seems to be associated with age. Initiation of the especial counseling on the institution that address to physical domain must be to promote the quality of life in all domain of the pregnant women. Keywords: Pregnant women; Health-related quality of life; Antenatal clinic

scholarly journals Compound Popular Content Caching Strategy in Named Data Networking

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 771 ◽  
Author(s):  
Naeem ◽  
Nor ◽  
Hassan ◽  
Kim
Keyword(s):  
Data Dissemination ◽  
Stretch Ratio ◽  
Data Traffic ◽  
Named Data Networking ◽  
Caching Strategy ◽  
Content Caching ◽  
Content Diversity ◽  
Cache Hit Ratio ◽  
Caching Mechanism ◽  
Data Networking

The aim of named data networking (NDN) is to develop an efficient data dissemination approach by implementing a cache module within the network. Caching is one of the most prominent modules of NDN that significantly enhances the Internet architecture. NDN-cache can reduce the expected flood of global data traffic by providing cache storage at intermediate nodes for transmitted contents, making data broadcasting in efficient way. It also reduces the content delivery time by caching popular content close to consumers. In this study, a new content caching mechanism named the compound popular content caching strategy (CPCCS) is proposed for efficient content dissemination and its performance is measured in terms of cache hit ratio, content diversity, and stretch. The CPCCS is extensively and comparatively studied with other NDN-based caching strategies, such as max-gain in-network caching (MAGIC), WAVE popularity-based caching strategy, hop-based probabilistic caching (HPC), LeafPopDown, most popular cache (MPC), cache capacity aware caching (CCAC), and ProbCache through simulations. The results shows that the CPCCS performs better in terms of the cache hit ratio, content diversity ratio, and stretch ratio than all other strategies.

scholarly journals Analysis of an SDN-Based Cooperative Caching Network with Heterogeneous Contents

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1491
Author(s):  
Qi Li ◽  
Xiaoxiang Wang ◽  
Dongyu Wang ◽  
Yibo Zhang ◽  
Yanwen Lan ◽  
...  
Keyword(s):  
Rapid Development ◽  
Mobile User ◽  
Base Station ◽  
Cooperative Caching ◽  
Software Defined Network ◽  
File Size ◽  
Caching Strategy ◽  
Content Caching ◽  
Data Coverage ◽  
Simulation Results

The ubiquity of data-enabled mobile devices and wireless-enabled data applications has fostered the rapid development of wireless content caching, which is an efficient approach to mitigating cellular traffic pressure. Considering the content characteristics and real caching circumstances, a software-defined network (SDN)-based cooperative caching system is presented. First, we define a new file block library with heterogeneous content attributes [file popularity, mobile user (MU) preference, file size]. An SDN-based three-tier caching network is presented in which the base station supplies control coverage for the entire macrocell and cache helpers (CHs), MUs with cache capacities offer data coverage. Using the ‘most popular content’ and ‘largest diversity content’, a distributed cooperative caching strategy is proposed in which the caches of the MUs store the most popular contents of the file block library to mitigate the effect of MU mobility, and those of the CHs store the remaining contents in a probabilistic caching manner to enrich the content diversity and reduce the MU caching pressure. The request meet probability (RMPro) is subsequently proposed, and the optimal caching distribution of the contents in the probabilistic caching strategy is obtained via optimization. Finally, using the result of RMPro optimization, we also analyze the content retrieval delays that occur when a typical MU requests a file block or a whole file. Simulation results demonstrate that the proposed caching system can achieve quasi-optimal revenue performance compared with other contrasting schemes.

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