scholarly journals A Simple Queuing Model for Molecular Communications Receivers

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7664
Author(s):  
Mauro Femminella ◽  
Gianluca Reali
Keyword(s):  
Communication Systems ◽  
Fundamental Property ◽  
Queuing Model ◽  
Modeling Tools ◽  
Proposed Model ◽  
Biological Target ◽  
Massive Number ◽  
Receiver Model ◽  
Communications System ◽  
Typical Scenario

The complexity of molecular communications system, involving a massive number of interacting entities, makes scalability a fundamental property of simulators and modeling tools. A typical scenario is that of targeted drug delivery systems, which makes use of biological nanomachines close to a biological target, able to release molecules in the diseased area. In this paper, we propose a simple although reliable receiver model for diffusion-based molecular communication systems tackling the time needed for analyzing such a system. The proposed model consists of using an equivalent markovian queuing model, which reproduces the aggregate behavior of thousands of receptors spread over the receiver surface. It takes into account not only the fact that the absorption of molecules can occur only through receptors, but also that absorption is not an instantaneous process, and may require a significant time during which the receptor is not available to bind to other molecules. Our results, expressed in terms of number of absorbed molecules and average number of busy receptors, demonstrate that the proposed approach is in good agreement with results obtained through particle-based simulations of a large number of receptors, although the time taken for obtaining the results with the proposed model is order of magnitudes lower than the simulation time. We believe that this model can be the precursor of novel class of models based on similar principles that allow realizing reliable simulations of much larger systems.

Modeling Bus Capacity for Bus Stops Using Queuing Theory and Diffusion Approximation

2021 ◽  
pp. 036119812110302
Author(s):  
Chao Wang ◽  
Weijie Chen ◽  
Yueru Xu ◽  
Zhirui Ye
Keyword(s):  
Approximation Method ◽  
Service Time ◽  
Diffusion Approximation ◽  
Coefficient Of Variation ◽  
Queuing Theory ◽  
Queuing Model ◽  
Bus Stop ◽  
Proposed Model ◽  
Bus Stops ◽  
Bus Service

For bus service quality and line capacity, one critical influencing factor is bus stop capacity. This paper proposes a bus capacity estimation method incorporating diffusion approximation and queuing theory for individual bus stops. A concurrent queuing system between public transportation vehicles and passengers can be used to describe the scenario of a bus stop. For most of the queuing systems, the explicit distributions of basic characteristics (e.g., waiting time, queue length, and busy period) are difficult to obtain. Therefore, the diffusion approximation method was introduced to deal with this theoretical gap in this study. In this method, a continuous diffusion process was applied to estimate the discrete queuing process. The proposed model was validated using relevant data from seven bus stops. As a comparison, two common methods— Highway Capacity Manual (HCM) formula and M/M/S queuing model (i.e., Poisson arrivals, exponential distribution for bus service time, and S number of berths)—were used to estimate the capacity of the bus stop. The mean absolute percentage error (MAPE) of the diffusion approximation method is 7.12%, while the MAPEs of the HCM method and M/M/S queuing model are 16.53% and 10.23%, respectively. Therefore, the proposed model is more accurate and reliable than the others. In addition, the influences of traffic intensity, bus arrival rate, coefficient of variation of bus arrival headway, service time, coefficient of variation of service time, and the number of bus berths on the capacity of bus stops are explored by sensitivity analyses.

Electricity demand forecasting using fuzzy hybrid intelligence-based seasonal models

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mehdi Khashei ◽  
Fatemeh Chahkoutahi
Keyword(s):  
Electricity Markets ◽  
Demand Forecasting ◽  
Load Forecasting ◽  
Multilayer Perceptrons ◽  
Modeling Tools ◽  
Content Type ◽  
Proposed Model ◽  
Hybrid Intelligence ◽  
Electricity Load ◽  
Electricity Load Forecasting

Purpose The purpose of this paper is to propose an extensiveness intelligent hybrid model to short-term load electricity forecast that can simultaneously model the seasonal complicated nonlinear uncertain patterns in the data. For this purpose, a fuzzy seasonal version of the multilayer perceptrons (MLP) is developed. Design/methodology/approach In this paper, an extended fuzzy seasonal version of classic MLP is proposed using basic concepts of seasonal modeling and fuzzy logic. The fundamental goal behind the proposed model is to improve the modeling comprehensiveness of traditional MLP in such a way that they can simultaneously model seasonal and fuzzy patterns and structures, in addition to the regular nonseasonal and crisp patterns and structures. Findings Eventually, the effectiveness and predictive capability of the proposed model are examined and compared with its components and some other models. Empirical results of the electricity load forecasting indicate that the proposed model can achieve more accurate and also lower risk rather than classic MLP and some other fuzzy/nonfuzzy, seasonal nonseasonal, statistical/intelligent models. Originality/value One of the most appropriate modeling tools and widely used techniques for electricity load forecasting is artificial neural networks (ANNs). The popularity of such models comes from their unique advantages such as nonlinearity, universally, generality, self-adaptively and so on. However, despite all benefits of these methods, owing to the specific features of electricity markets and also simultaneously existing different patterns and structures in the electrical data sets, they are insufficient to achieve decided forecasts, lonely. The major weaknesses of ANNs for achieving more accurate, low-risk results are seasonality and uncertainty. In this paper, the ability of the modeling seasonal and uncertain patterns has been added to other unique capabilities of traditional MLP in complex nonlinear patterns modeling.

Research on Application of Tunable Dispersion Compensation Technology in Optical Fiber Communication Systems

2013 ◽  
Vol 401-403 ◽  
pp. 1956-1959
Author(s):  
Wen Xuan Gai
Keyword(s):  
Communication Systems ◽  
Dispersion Compensation ◽  
Optical Fiber Communication ◽  
Fiber Grating ◽  
Basic Principles ◽  
Fiber Communication ◽  
Future Direction ◽  
Chirped Fiber Grating ◽  
Research On Application ◽  
Communications System

For high bit-rate optical communications system, the changes in temperature or power fluctuations are due to the dispersion of the dispersion tolerance than the system. Therefore, the dispersion compensation unit must have the functionality to adapt to the dynamic generation of tunable optical communication network development. This article describes several dynamic tunable compensation techniques and the basic principles of the performance characteristics of the situation at home and abroad, including the chirped fiber grating method, the virtual image phased array method, GT interferometer method, the array method and the planar waveguide grating method, and a brief discussion of tunable dispersion compensation technology in the future direction of development.

scholarly journals Impact of Prioritization on the Outpatient Queuing System in the Emergency Department with Limited Medical Resources

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 796 ◽  
Author(s):  
Ao Zhang ◽  
Xiaomin Zhu ◽  
Qian Lu ◽  
Runtong Zhang
Keyword(s):  
Emergency Department ◽  
Emergency Services ◽  
Service System ◽  
Queuing System ◽  
Hospital Service ◽  
Key Factors ◽  
Queuing Model ◽  
Medical Resources ◽  
Proposed Model

The emergency department has an irreplaceable role in the hospital service system because of the characteristics of its emergency services. In this paper, a new patient queuing model with priority weight is proposed to optimize the management of emergency department services. Compared with classical queuing rules, the proposed model takes into consideration the key factors of service and the first-come-first-served queuing rule in emergency services. According to some related queuing indicators, the optimization of emergency services is discussed. Finally, a case study and some compared analysis are conducted to illustrate the practicability of the proposed model.

A Hybrid Multiple Parallel Queuing Model to Enhance QoS in Cloud Computing

2020 ◽  
Vol 12 (1) ◽  
pp. 18-34 ◽  
Author(s):  
Shahbaz Afzal ◽  
G. Kavitha
Keyword(s):  
Cloud Computing ◽  
Response Time ◽  
Waiting Time ◽  
Queue Length ◽  
Utilization Rate ◽  
Queuing Model ◽  
Total Response Time ◽  
Proposed Model ◽  
Mathematical Equations ◽  
And Performance

Among the different QoS metrics and parameters considered in cloud computing are the waiting time of cloud tasks, execution time of tasks in VM's, and the utilization rate of servers. The proposed model was developed to overcome some of the pitfalls in the existing systems among which are sub-optimal markdown in the queue length, waiting time, response time, and server utilization rate. The proposed model contemplates on the enhancement of these metrics using a Hybrid Multiple Parallel Queuing approach with a joint implementation of M/M/1: ∞ and M/M/s: N/FCFS to achieve the desired objectives. A neoteric set of mathematical equations have been formulated to validate the efficiency and performance of the hybrid queuing model. The results have been validated with reference to the workload traces of Bit Brains infrastructure provider. The results obtained indicate the significant reduction in the queue length by 60.93 percent, waiting time in the queue by 73.85 percent, and total response time by 97.51%.

scholarly journals A receiver model for optical fiber communication systems with arbitrarily polarized noise

2005 ◽  
Vol 23 (3) ◽  
pp. 1478-1490 ◽  
Author(s):  
I.T. Lima ◽  
A.O. Lima ◽  
Yu Sun ◽  
Hua Jiao ◽  
J. Zweck ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Communication Systems ◽  
Optical Fiber Communication ◽  
Fiber Communication ◽  
Receiver Model

Temperature dependence of turn-on time delay of semiconductor laser diode: Theoretical analysis

2010 ◽  
Vol 18 (4) ◽  
Author(s):  
M.S. Ab Rahman ◽  
M.R. Hassan
Keyword(s):  
Time Delay ◽  
Temperature Dependence ◽  
Semiconductor Laser ◽  
Laser Diode ◽  
Communication Systems ◽  
Recombination Coefficient ◽  
Turn On ◽  
Proposed Model ◽  
Wide Range ◽  
Dc Bias

AbstractTemperature dependence of the turn-on time delay (ton) of uncooled semiconductor laser diodes biased below and above threshold is analyzed in presence of data pattern effect. We show that even when the laser is biased at or slightly above threshold, the increase in temperature of operation will lead to increase in the threshold carrier (Nth) and consequently the laser diode will be biased below the threshold again and a significant value of ton will be produced. Thus, knowledge about a value of dc-bias current required to achieve zero ton within wide range of temperature degrees is important when considering uncooled laser diode in high-speed optical communication systems. The temperature dependence of ton is calculated according to the temperature dependence of Nth and Auger recombination coefficient (C) and not by the well-know exponentional relationship of threshold current with temperature. The temperature dependence of Nth is calculated according to the temperature dependence of laser cavity parameters. Advanced analytical model is derived in term of carrier density, recombination coefficients and the injection current (Iinj). The validity of proposed model is confirmed by a numerical method. In addition, approximated models are included where under specified assumptions the proposed model reduces to the well-known approximate models of ton. According to our typical values and at a specified value of modulation current, the dc-bias one (Iib) should be increased from Iib = Ith to Iib ≈ 1.25 and 1.5Ith in order to achieve approximately zero ton when the temperature increases from 25°C to 55°C and 85°C, respectively.

Infrared control of slow light in a slab doped by InGaN/GaN quantum dot nanostructure

2015 ◽  
Vol 29 (05) ◽  
pp. 1550012
Author(s):  
Hossein Jafarzadeh ◽  
Elnaz Ahmadi Sangachin ◽  
Seyyed Hossein Asadpour
Keyword(s):  
Quantum Dot ◽  
Communication Systems ◽  
Light Propagation ◽  
Slow Light ◽  
Optical Systems ◽  
Proposed Model ◽  
Ultrahigh Density ◽  
Fast Light ◽  
Slow And Fast Light ◽  
Signal Field

In this paper, we proposed a model for controlling the group velocity of the transmitted and reflected pulses in a slab medium doped by four-level quantum dot nanostructure. Here, an infrared signal field interacted by quantum dot nanostructure can affect the behavior of reflected and transmitted pulses. We show that in the presence and absence of infrared pulses, the other controllable parameters have essential roles for controlling the slow and fast light propagation through the medium. Moreover, we found that the simultaneous slow and fast light can be obtained for the transmitted and reflected pulses by infrared signal field. Our proposed model may be useful for ultrahigh density optical memories in quantum communication systems or in various fields of all-optical systems.

scholarly journals Dynamic Resource Scheduling Cloud using Enhanced Queuing Model

2020 ◽  
Vol 9 (1) ◽  
pp. 2064-2071
Keyword(s):  
Resource Allocation ◽  
Real Time ◽  
Cloud Provider ◽  
Single Server ◽  
Queuing Model ◽  
Proposed Model ◽  
Multiple Servers ◽  
Resource Requirements ◽  
Dynamic Resource ◽  
Lock In

The important goal of cloud computing is to offer larger data center that satisfies the storage requirements of the customer. The entire data can’t be saved in a single server. Cloud provider (CP) has cluster of servers to fulfill the cloud request from various real time applications. The data is fragmented in multiple servers to maintain availability. Since the data request of a customer needs data from various servers, there is a possibility of attaining dead lock. In this paper, an enhanced queuing model is proposed where the cloud request (CR) is received in queuing manner for allocation of resources. A session is created for the CR with the CP resource allocation from cloud severs. This enables to put constraint on the number of CR making a session with CP to avoid resource suppression. The Wait for Resource algorithm is used for allocating the server resources to a CR without deadlock in a session. This enables to forecast the resource requirements prior to resource allocation phase in a session. This makes the dynamic resource allocation efficient and free of deadlock. The results obtained evaluates the proposed model and helps the CP in dynamically choosing the number of server nodes necessary to achieve better performance for an real time application.

THE BASICS OF SELECTING THE OPTIMAL PARAMETERS OF ERROR-CORRECTING CODES FOR TELECOMMUNICATION SYSTEMS

2020 ◽  
Author(s):  
М.А. Быховский
Keyword(s):  
Communication Systems ◽  
Ldpc Code ◽  
Satellite Communications ◽  
Error Correcting Codes ◽  
Rs Codes ◽  
Transmission Reliability ◽  
Multidimensional Signal ◽  
Large Length ◽  
Parity Check Codes ◽  
Communications System

Рассмотрены основные принципы выбора параметров помехоустойчивых кодов для систем связи. Приведены формулы для вероятности ошибки декодирования разных кодов в зависимости от их длины и от вероятности ошибки демодуляции сигналов. Показано, что коды Рида-Соломона (RS) достаточно большой длины позволяют обеспечить высокую помехоустойчивость приема сообщений. Показано также, что в системе связи, в которой сообщения передаются с помощью многомерных ансамблей сигналов, а помехоустойчивые коды не используются, высокая помехоустойчивость приема сообщений обеспечивается при предельно малом отношении сигнал/шум на входе демодулятора. Выполнено сравнение параметров систем связи с кодами RS и спутниковой связи стандарта DVB-S2 с двоичными кодами с малой плотностью проверочных символов (LDPC). Показано, что высокая надежность передачи в системе обеспечивается при использовании с кода RS, имеющего существенно меньшую длину, чем у кода LDPC. The basic principles of selection of parameters of error- correcting codes for communication systems are considered. Formulas, that allow determining the probability of decoding errors of different codes depending on their length and the probability demodulation errors of signals, are given. It is shown that Reed-Solomon (RS) codes of a sufficiently large length make it possible to ensure high noise immunity of receiving messages. It is also shown that in a communication system in which messages are transmitted using multidimensional signal ensembles, and error-correcting codes are not used, messages can be transmitted at a given speed with an extremely small signal/noise ratio at the input of the demodulator. A comparison of the parameters of communication systems with RS codes and the DVB-S2 satellite communications system with binary low-density parity-check codes (LDPC) is performed. It is shown that high transmission reliability in the system is achieved by using an RS code having a significantly shorter length than the LDPC code.

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