scholarly journals Efficient Periodic Broadcasting for Mobile Networks at Small Client Receiving Bandwidth and Buffering Space

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Hsiang-Fu Yu ◽  
Yao-Tien Wang ◽  
Jong-Yih Kuo ◽  
Chu-Yi Chien
Keyword(s):  
Waiting Time ◽  
Mobile Networks ◽  
Buffer Size ◽  
System Throughput ◽  
Video Server ◽  
Extensive Analysis ◽  
Channel Bandwidth ◽  
Periodic Broadcasting ◽  
Simulation Results ◽  
To Receive

Periodic broadcasting is an effective approach for delivering popular videos. In general, this approach does not provide interactive (i.e., VCR) functions, and thus a client can tolerate playback latency from a video server. The concept behind the approach is partitioning a video into multiple segments, which are then broadcast across individual communication channels in terms of IP multicast. The method improves system throughput by allowing numerous clients to share the channels. For many broadcasting schemes, client receiving bandwidth must equal server broadcasting bandwidth. This limitation causes these schemes to be infeasible in mobile networks because increasing receiving bandwidth at all client sites is expensive, as well as difficult. To alleviate this problem, the fibonacci broadcasting (FiB) scheme allows a client with only two-channel bandwidth to receive video segments. In comparison with other similar schemes, FiB yields smallest waiting time. Extending FiB, this work proposes a new scheme (called FiB+) to achieve smaller client buffering space and the same waiting time under two-channel receiving bandwidth. Extensive analysis shows that FiB+ can yield 34.5% smaller client buffer size than that of FiB. Further simulation results also indicate that FiB+ requires lower client buffering space than several previous schemes.

scholarly journals D2D Mobile Relaying Meets NOMA—Part I: A Biform Game Analysis

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 702 ◽  
Author(s):  
Safaa Driouech ◽  
Essaid Sabir ◽  
Mounir Ghogho ◽  
El-Mehdi Amhoud
Keyword(s):  
Mobile Networks ◽  
Nash Equilibria ◽  
Channel Model ◽  
System Throughput ◽  
Mixed Strategies ◽  
Game Analysis ◽  
Active Devices ◽  
Communication Paradigm ◽  
Global Performance ◽  
Simulation Results

Structureless communications such as Device-to-Device (D2D) relaying are undeniably of paramount importance to improving the performance of today’s mobile networks. Such a communication paradigm requires implementing a certain level of intelligence at device level, allowing to interact with the environment and select proper decisions. However, decentralizing decision making sometimes may induce some paradoxical outcomes resulting, therefore, in a performance drop, which sustains the design of self-organizing, yet efficient systems. Here, each device decides either to directly connect to the eNodeB or get access via another device through a D2D link. Given the set of active devices and the channel model, we derive the outage probability for both cellular link and D2D link, and compute the system throughput. We capture the device behavior using a biform game perspective. In the first part of this article, we analyze the pure and mixed Nash equilibria of the induced game where each device seeks to maximize its own throughput. Our framework allows us to analyse and predict the system’s performance. The second part of this article is devoted to implement two Reinforcement Learning (RL) algorithms enabling devices to self-organize themselves and learn their equilibrium pure/mixed strategies, in a fully distributed fashion. Simulation results show that offloading the network by means of D2D-relaying improves per device throughput. Moreover, detailed analysis on how the network parameters affect the global performance is provided.

scholarly journals A Proposed Adaptive Bitrate Scheme Based on Bandwidth Prediction Algorithm for Smoothly Video Streaming

2021 ◽  
Vol 27 (1) ◽  
pp. 112-129
Author(s):  
Saba Qasim Jabbar ◽  
Dheyaa Jasim Kadhim
Keyword(s):  
Video Streaming ◽  
Video Quality ◽  
Prediction Algorithm ◽  
Buffer Size ◽  
Video Playback ◽  
Buffer Occupancy ◽  
Simulation Results ◽  
Streaming Technology ◽  
The Impact ◽  
Buffer Structure

A robust video-bitrate adaptive scheme at client-aspect plays a significant role in keeping a good quality of video streaming technology experience. Video quality affects the amount of time the video has turned off playing due to the unfilled buffer state. Therefore to maintain a video streaming continuously with smooth bandwidth fluctuation, a video buffer structure based on adapting the video bitrate is considered in this work. Initially, the video buffer structure is formulated as an optimal control-theoretic problem that combines both video bitrate and video buffer feedback signals. While protecting the video buffer occupancy from exceeding the limited operating level can provide continuous video streaming, it may also cause a video bitrate oscillation. So the video buffer structure is adjusted by adding two thresholds as operating points for overflow and underflow states to filter the impact of throughput fluctuation on video buffer occupancy level. Then a bandwidth prediction algorithm is proposed for enhancing the performance of video bitrate adaptation. This algorithm's work depends on the current video buffer level, video bitrate of the previous segment, and iterative throughput measurements to predict the best video bitrate for the next segment. Simulation results show that reserving a bandwidth margin is better in adapting the video bitrate under bandwidth variation and then reducing the risk of video playback freezing. Simulation results proved that the playback freezing happens two times: firstly, when there is no bandwidth margin used and secondly, when the bandwidth margin is high while smooth video bitrate is obtained with moderate value. The proposed scheme is compared with other two schemes such as smoothed throughput rate (STR) and Buffer Based Rate (BBR) in terms of prediction error, QoE preferences, buffer size, and startup delay time, then the proposed scheme outperforms these schemes in attaining smooth video bitrates and continuous video playback.

scholarly journals Factors Influencing Utilization of Ultrasound Scan Services among Pregnant Mothers at Ndejje Health Center IV, Wakiso District

2020 ◽  
Author(s):  
◽  
Angella Nakimera
Keyword(s):  
Health Facility ◽  
Waiting Time ◽  
Health Centre ◽  
Ultrasound Scan ◽  
Related Factors ◽  
Cross Sectional ◽  
Factors Influencing ◽  
Study Results ◽  
To Receive ◽  
Pregnant Mothers

Abstract Background: A study was carried out to identify the factors influencing the utilization of ultrasound scan services among pregnant mothers at Ndejje Health Centre IV, Wakiso District. Methodology: The study design was descriptive and cross-sectional and it employed both quantitative and qualitative data collection methods. A sample size of 30 respondents was selected using a simple random sampling procedure. An interview guide was used to collect data. Results: The study revealed various factors influencing the utilization of ultrasound scan services among pregnant mothers. For example, although all 30 (100%) had ever heard about ultrasound scan services, most 20 (66.7%) had ever used ultrasound scan services once 10 (50%) and 12 (60%) used the services in the 3rd trimester due to factors including 20 (66.7%) of ultrasound scan services, 21 (70%) having fears about using ultrasound scan services including 14 (66.7%) fear that the scan would identify bad conditions on the baby, 18 (60%) lacked partner support. The study results also revealed that respondents faced various health facility factors which influenced the utilization of ultrasound scan services. For example, most 20 (66.7%) respondents reported that Ndejje Health Centre IV was not equipped to provide ultrasound scan services due to 12 (60%) frequent breakdown and poor maintenance of equipment which led to 18 (60%) ultrasound scan services not being readily available, 12 (60%) long waiting time to receive services as most waited more than 2 hours to receive services. Conclusion and recommendations: Respondents faced various and health facility-related factors which influenced their utilization of ultrasound scan services. The key recommendations included ready availability of services through regular and timely maintenance of equipment, improving efficiency, and reducing waiting time as well as improved health education of mothers about the importance of using the services.

scholarly journals An Improved Mobility Aware Relaying Scheme for Body Area Networks

2020 ◽  
Author(s):  
Costas Michaelides ◽  
Maria Iloridou ◽  
Foteini-Niovi Pavlidou
Keyword(s):  
Random Access ◽  
High Mobility ◽  
Body Area Networks ◽  
Ieee 802.15.6 ◽  
Body Area ◽  
Star Topology ◽  
Packet Delivery ◽  
Safety Regulations ◽  
Simulation Results ◽  
To Receive

Communication in Body Area Networks (BANs) involves weak signals, due to safety regulations, huge pathloss from the absorption and usually high mobility. In this work, we introduce an improved mobility aware relaying scheme for BANs, as an alternative to the two-hop star topology extension of IEEE 802.15.6-2012, in order to enhance packet delivery. Specifically, an emergency phase (EP) is added after the regular random access phase (RAP1) of the superframe and the connected nodes transmit rescue beacons to reach disconnected nodes. When a disconnected node receives a rescue beacon, it participates in the current EP. The packets are buffered and relayed to the hub by the connected nodes. Simulation results show that it is feasible to receive more packets compared to the standard with a justified increase of energy consumption due to random access which is compensated with increased packet delivery.

scholarly journals Marine Pollution Mitigation by Waste Oils Recycling Onboard Ships: Technical Feasibility and Need for New Policy and Regulations

2020 ◽  
Vol 7 ◽  
Author(s):  
Michela Mazzoccoli ◽  
Marco Altosole ◽  
Veronica Vigna ◽  
Barbara Bosio ◽  
Elisabetta Arato
Keyword(s):  
Marine Pollution ◽  
Cost Savings ◽  
Waste Recycling ◽  
Fuel Oil ◽  
Waste Oil ◽  
Marine Fuel ◽  
Waste Oils ◽  
Simulation Results ◽  
Oily Waste ◽  
To Receive

About 80% of the total pollution from ships is caused by operational oil discharges into the sea, often made deliberately and in violation of international rules; the main reasons can be due to cost savings or lack of adequate facilities in ports to receive waste oils. Therefore, reducing waste oil discharges is crucial for a proper protection of the marine environment. In this regard, the paper presents the preliminary feasibility of a particular waste recycling technology, aimed at obtaining marine fuel oil from sludge, through a pyrolysis process to be carried out in a small reactor onboard. The originality of the research consists in the adaptation of pyrolysis to oily waste produced by ships, since this technology is traditionally applied to solid waste and biomass. Furthermore, the plant has to be designed for operation on board the ship, therefore under very different constraints compared to traditional land plants. Although the preliminary lab tests and simulation results in the chemical process are promising enough, there are still some technical criticalities due to the energy optimization of the reactor for an efficient use onboard of the whole system. In addition, the possibility of recycling waste, directly onboard ships, is not yet covered by mandatory regulations, which is why shipowners generally still feel unmotivated to invest in such technologies.

Research and Implement of an Improved Frame-Slotted ALOHA Anti-Collision Algorithm

2014 ◽  
Vol 945-949 ◽  
pp. 2519-2522
Author(s):  
Li He ◽  
Gai Ping Liu ◽  
Chuan Yuan Han
Keyword(s):  
System Throughput ◽  
Slotted Aloha ◽  
C Language ◽  
Key Technology ◽  
Rfid System ◽  
Simulation Results

The anti-collision algorithm is the key technology of RFID system. Firstly, this paper studied frame-slotted ALOHA anti-collision algorithm, in order to solve the shortcomings of ALOHA algorithm, an improved anti-collision algorithm is proposed based on grouping mechanism, and it also carried out the simulation experiences using the C# language under the .NET platform. The simulation results indicate that the improved algorithms can increase RFID system throughput.

Don’t Call Us, We’ll Call You: An Empirical Study of Caller Behavior Under a Callback Option

2020 ◽  
Author(s):  
Brett A. Hathaway ◽  
Seyed M. Emadi ◽  
Vinayak Deshpande
Keyword(s):  
Service Quality ◽  
Waiting Time ◽  
Operations Management ◽  
Call Center ◽  
Structural Model ◽  
Waiting Times ◽  
System Throughput ◽  
Service Channel ◽  
Data Driven Approach ◽  
Alternative Service

Although call centers have recently invested in callback technology, the effects of this innovation on call center performance are not clearly understood. In this paper, we take a data-driven approach to quantify the operational impact of offering callbacks under a variety of callback policies. To achieve this goal, we formulate a structural model of the caller decision-making process under a callback option and impute their underlying preferences from data. Our model estimates shed light on caller preferences under a callback option. We find that callers experience three to six times less discomfort per unit of time while waiting for callbacks than while waiting in queue, suggesting that offering callbacks can increase service quality by channeling callers to an alternative service channel where they experience less discomfort while waiting. However, after controlling for expected waiting times, callers generally prefer waiting in a queue over accepting a callback and waiting offline. This suggests that managers of this call center may want to spend efforts in educating their customers on the benefits of the callback option. Using the callers’ imputed preferences, we are able to conduct counterfactual analyses of how various callback policies affect the performance of this call center. We find that in this call center, offering to hold the callers’ spot in line or to call back within a window (guaranteed timeframe) reduces average online waiting time (the average time callers wait on the phone) by up to 71% and improves service quality by decreasing callers’ average incurred waiting cost by up to 46%. Moreover, we find that offering callbacks as a demand postponement strategy during periods of temporary congestion reduces average online waiting time by up to 86%, increases service quality by up to 54%, and increases system throughput by up to 2.1%. This paper was accepted by Vishal Gaur, operations management.

scholarly journals An Efficient Periodic Broadcasting with Small Latency and Buffer Demand for Near Video on Demand

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ying-Nan Chen ◽  
Li-Ming Tseng
Keyword(s):  
Waiting Time ◽  
Video On Demand ◽  
Significant Fraction ◽  
On Demand ◽  
Periodic Broadcasting ◽  
Fixed Delay

Broadcasting Protocols can efficiently transmit videos that simultaneously shared by clients with partitioning the videos into segments. Many studies focus on decreasing clients' waiting time, such as the fixed-delay pagoda broadcasting (FDPB) and the harmonic broadcasting schemes. However, limited-capability client devices such as PDAs and set-top boxes (STBs) suffer from storing a significant fraction of each video while it is being watched. How to reduce clients' buffer demands is thus an important issue. Related works include the staircase broadcasting (SB), the reverse fast broadcasting (RFB), and the hybrid broadcasting (HyB) schemes. This work improves FDPB to save client buffering space as well as waiting time. In comparison with SB, RFB, and HyB, the improved FDPB scheme can yield the smallest waiting time under the same buffer requirements.

Cardinality Estimation-Based Adaptive Multi-Tree Splitting Algorithm for RFID System

2012 ◽  
Vol 239-240 ◽  
pp. 1373-1376
Author(s):  
Yong Tan ◽  
Gui Xiong Liu ◽  
Guo Guang Wu
Keyword(s):  
System Throughput ◽  
Depth Information ◽  
Splitting Algorithm ◽  
Tag Identification ◽  
Cardinality Estimation ◽  
Rfid System ◽  
Average Total Number ◽  
Simulation Results

This paper proposes a cardinality estimation-based adaptive multi-tree splitting (CEAMS) algorithm. Tag number is estimated by using the depth information obtained from the first tag identification and adaptively assigns the splitting strategy according to the splitting subset rule table. Simulation results show that the average total number of timeslots can be reduced by 65% compared with DBS and the system throughput is about 0.52 when the number of tags ranged from 5 ~ 1000.

An Advanced Self-Adaptive Iterative Decoding Scheme Based on Stopping Criterion

2011 ◽  
Vol 179-180 ◽  
pp. 167-173 ◽  
Author(s):  
Shu Yang Liu ◽  
Jian Ping Li ◽  
Chao Shi Cai
Keyword(s):  
Turbo Codes ◽  
Iterative Decoding ◽  
Stopping Criterion ◽  
Lower Complexity ◽  
Simulation Results ◽  
To Receive ◽  
Self Adaptive

This paper proposes an advanced iterative decoding scheme based on stopping criterion for BICM-ID embedded turbo codes. A fixed iterative number scheme has been used in the receiver and lower complexity than the conventional schedule can be achieved. To acquire a smaller total iterative number and fewer calculations of CE, the maximum and minimum iterative numbers (Imax/Imin) are introduced in this proposed scheme. However, iterative numbers which correspond to different SNRs are varied. In order to receive better flexibility, both Imax and Imin, whose values are not unique, are determined by the statistics of the average iterative numbers and the CG criterion. Simulation results confirm that, compared with the fixed iterative number scheme, similar BER performances and much lower complexity can be achieved. Further improvement of the adaptability results from this self-adaptive option of Imax/Imin.

Sign in / Sign up

Export Citation Format

Share Document