Transmission Delay Characteristics Research Articles

Quasi-dynamic modeling and simulation of district heating systems: A laplace transform-based approach

The technological development direction for China's green and low-carbon energy transformation is constructing a multi-energy collaborative smart integrated energy system. As an essential subsystem of energy systems in northern China, district heating system (DHS) plays a crucial role in ensuring people's livelihood. The energy system transformation and the development of the new generation of heating systems impose increasing demands on the simulation computations of regional heating systems. This paper establishes a quasi-dynamic model for heating systems based on the Laplace transform as the foundation. It transforms the continuous thermal dynamics in the time domain into the Laplace domain for quantitatively analyzing the heat transfer loss characteristics and transmission delay characteristics in the heat transport process. Furthermore, it converts the internal complex transmission processes of the system into equivalent source-load boundary conditions to obtain a thermal state analysis model with clear physical significance. This approach significantly reduces the computational complexity of network analysis while ensuring computational accuracy. The established quasi-dynamic model is applied to cases of different scales. The computational results are compared and validated against the commercial simulation software Apros and actual operational data. The urban DHS case study calculation results show a mass flow mean relative error of 3.02% and a supply/return water temperature mean relative error of 2.46%, supporting more refined dynamic scheduling.

Simulation of Low-Power Shift Registers Using the MTCMOS Method with a Wide Selection of Transistors

The method of huge integrating involves implementing a significant transistor count in an extremely condensed space. Combinatorial logic has shown to be particularly effective in quantum computing as well as other designing applications. In VLSI design, the primary goal is to cut down on power consumption as well as latency. For the purpose of establishing technology and supporting the increased use of electrical machines, it is vital to decrease sub-threshold current flowing for large strains. This research explores the feasibility of implementing a shift register and without the Multi-threshold CMOS (MTCMOS) approach. At the process technology of 0.18 µm, 0.12 µm, and 90 nm, an investigation into the power loss and transmission delay characteristics of a variety of flip-flops is carried out. As technology gets shrunk, the amount of power lost through leakage rises. Using the greatest technique among all run time strategies, namely MTCMOS, helps to limit the amount of power lost due to leakage. The purpose of this article is to give a comparison between various traditional flip-flops and the TSPC flip-flop with regard to power usage, diffusion delays, product of delay-power (PDP), area, and power flow using the findings obtained from the Microwind simulator.

Distributed Thermal Energy Storage Configuration of an Urban Electric and Heat Integrated Energy System Considering Medium Temperature Characteristics

Distributed thermal energy storage (DTES) provides specific opportunities to realize the sustainable and economic operation of urban electric heat integrated energy systems (UEHIES). However, the construction of the theory of the model and the configuration method of thermal storage for distributed application are still challenging. This paper analyzes the heat absorption and release process between the DTES internal heat storage medium and the heat network transfer medium, refines the relationship between heat transfer power and temperature characteristics, and establishes a water thermal energy storage and electric heater phase change thermal energy storage model, considering medium temperature characteristics. Combined with the temperature transmission delay characteristics of a heat network, a two-stage optimal configuration model of DTES for UEHIES is proposed. The results show that considering the temperature characteristics in the configuration method can accurately reflect the performance of DTES, enhance wind power utilization, improve the operation efficiency of energy equipment, and reduce the cost of the system.

Operation optimization of integrated energy systems based on heat storage characteristics of heating network

AbstractWith the development of multi‐energy technology, the electric‐heat integrated energy system has become an important research direction for multi‐energy joint supply. The dynamic characteristics and energy storage capacity of heat supply network provide potential for joint dispatching of electric heating energy system. Aiming at the problem of electric‐heat joint dispatching, this paper presents an operation optimization model of electric‐heat integrated energy system considering the virtual energy storage characteristics of heat supply network. Firstly, according to the characteristics of transmission delay and user temperature fuzzy, the virtual energy storage characteristics of heat supply network are studied, and a model of the dynamic transfer of energy in the heat system was built. Then, the operation optimization model of the electric‐heat integrated energy system is established to minimize the operation cost. In order to improve the robustness of scheduling optimization results, the Monte Carlo Simulation embedded Quantum Particle Swarm Optimization algorithm is proposed to solve the model. In order to prove the validity of the proposed model, this paper selects a park (a 36 node thermal system) in the northwest region of China as a simulation case. The results show that the operation optimization method considering the virtual energy storage of heat supply network will greatly enhance the complementary potential of the electric‐heat integrated energy system and reduce the operation cost of the system.

Data Transmission Delay Characteristics of the Internet

Data Transmission Delay Characteristics of the Internet

Performance evaluation of 32 kbits/s real-time and dual-direction video communication system for wireless channels

This paper describes the construction and performance evaluation of a mobile video communication system composed of an H.263 video encoder, decoder, and RF transceiver equipment. It can establish a video connection using a 32 kbits/s wireless channel because it uses automatic repeat request (ARQ) as the error control scheme. Retransmission control can produce excessive transmission delay, but the improved ARQ protocol and coding-rate control scheme adopted by this system minimizes the delay. This ARQ protocol uses short ARQ frame length and an acknowledgement/negative acknowledgement (ACK/NAK) indicator. The coding-rate control scheme uses backward NAK signals to reduce the coding rate of the video encoder as necessary. We measure the transmission delay characteristics of this video system and confirm that the proposed scheme can reduce the delay over a noisy channel. Subjective assessment tests involving videophone usage are also conducted. Test results show that in a noisy channel (BER=3/spl times/10/sup -3/), this system can achieve the same mean opinion store as in a noiseless channel.

Priority Go-Back-N ARQ schemes

The go-back-N scheme is one of the error control methods in the satellite link. Various improvements have been made on this scheme, and the resulting throughput characteristics and packet delay characteristics have been described. However, in those methods, the priority of the class of the packet to be transmitted is not considered. This paper discusses the go-back-N scheme where priority rules are useful when several packets with different priority classes are to be transmitted on the satellite link are introduced. Two priority rules are introduced: nonpreemptive priority queueing and preemptive priority queueing. The go-back-N ARQ scheme with those priority rules can easily be realized by adding the packet sort function to the transmitter buffer in the conventional basic go-back-N ARQ scheme. The traffic analysis is made of the go-back-N ARQ scheme with those two priority rules for an arbitrary number of priority classes, and the packet delay expression is derived for each class. Then by numerical calculation examples, the average packet transmission delay characteristics in the two methods are examined.