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The Internet of Vehicles (IoV) aims to perceive, compute, and process environmental data in a collaborative manner. Previous works focus on data sharing between vehicles, but a large amount of data will lead to redundant transmission and network congestion. In addition, security and privacy issues prevent these nodes from participating in the sharing process. Knowledge is extracted from data through machine learning (ML) and shared in the form of small-scale well-trained model parameters, which improves collaborative learning more effectively and relieves network pressure. While traditional ML algorithms are not suitable for distributed IoV with local characteristics. Based on this, this paper first divides the vehicles into multiple regions and proposes a Regional Federated Learning (RFL) framework, in which all regions maintain their own learning models, i.e. knowledge. We design a reputation mechanism to measure the reliability of vehicles participating in RFL. To address the security challenges brought by the untrusted centralized trading market, we propose a blockchain-enhanced knowledge trading framework, in which an authorized market agency coordinates the trading quickly. We model the optimal pricing mechanism as a non-cooperative game, taking into account the competition among all knowledge providers. Numerical simulation shows that the proposed reputation mechanism improves the accuracy of knowledge up to 18%, and the optimal knowledge pricing mechanism effectively increases the utility of market.

In this paper, a multivariate regression transform (MRT) is proposed for pulse-amplitude-modulated-based hybrid optical orthogonal frequency division multiplexing (PHO-OFDM) visible light communications (VLC). PHO-OFDM is a hybrid modulation scheme that combines pulse amplitude modulated discrete multitone (PAM-DMT) and DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) for simultaneous transmission. The proposed method reduces the peak-to-average power ratio of PHO-OFDM to improve its system performance. Complementary cumulative distribution function simulation results show that the proposed method can effectively mitigate the PAPR of PHO-OFDM under different constellation combinations.

Opportunistic network mobile user-nodes location prediction can help to collect the data, improve the dynamic network and help to decrease the problems which include the delay, low success rate, high storage space energy consume and so on, which are the results of the blindness in the process of delivery. In this paper, a mobile node location prediction algorithm base on the Multi-Order Markov prediction model as the initial forecast, and then use social-relationship which is closely linked to the node to optimize the algorithm. Experimental results show that the proposed algorithm is better than the single Multi-Order Markov model.

Through simulating the process of energy storage heating floor contain phase change material (PCM), the action and function of PCM in building energy storage are discussed. Analysis and numerical simulation the energy storage process in building structure with PCM packaging module, discussion the relation of temperature distribution, heat condition, energy storage and discharge time and PCM efficiency to PCM models arrangement in building structure. To satisfy the floor heating energy storage requirement, the optimum PCM models arrangement has been given.

In this paper numerical simulated the thermal properties of solar air collector. With the ray-tracing solar load model provided by Fluent software, the solar radiation heat flux can be solve using radiation heat transfer equation, and then consider loading radiation heat into the source terms of the energy equation. The thermal effects rules of air flow and heat transfer in the collector box, temperature fields as well as the wind speed and solar radiation and other related factors under the different conditions have been discussed and analyzed.

This paper adopts the method of Fluent software simulation and simulates research the thermal performance of a solar air collector's with porous and fold lined. Changes in the structure of the collector plates whether the openings, folded plate and the plate hole collector aspects to impact performance are discussed. In order to have comparable, to simulate in the intensity of solar radiation, wind speed and imported air supply means, collector plates and glass cover settings such as radiation carried out under identical conditions. By simulating the temperature distribution, flow distribution of the collector and the internal air, it can be obtain the conclusions: in the collector plates to keep the same shape, hole board than non-hole plate uneven temperature distribution significantly, and local overheating, non-hole lead was the heat collector plate collector thermal efficiency with the collector plate lower than the hole; the hole in the collector plate to keep the same rate, opening flat and folded plate openings due to air within the collector differences in flow pattern on the plate led to overheating, increasing the external environment, heat loss, solar collector performance decreases.

Of a placement at the roof of a building using solar collectors to heating the air thermal properties were studied. Introduction a unit of the air flowing through the solar radiation collector temperature rise that characterized the parameters of a combination of collector, through measuring the thermal performance of the relevant factors of collector, such as outlet temperature, export air speed and solar radiation intensity under different conditions at the transition season, the affect of outdoor air temperature with solar radiation intensity and changes of the solar collector temperature rise with the export air speed and solar radiation effects have been explored. Experiments obtained the rule of the outdoor air temperature delayed action and continuity as solar heating during the test of local solar radiation intensity, given the changes trend of solar collector temperature rise with air speed and recommend the use of a reasonable collector temperature rise range.

On the base of the getting best action of the phase change material (PCM) properties, a new radiant heating structure of the energy storage floor by solar hot water is designed, which was to put heat pipes in PCM layer, without concrete in it. The PCM thermal storage time is mainly studied when the floor surface temperature is admired under different low-temperature hot water temperatures. With the method of enthalpy, the PCM heat storage time was mainly studied under different supply water temperatures, different supply water flows, different distance between water wipe in the floor construction, different floor covers and different insulation conditions.

In this article, the heat model with solar panel composite wall structure was set up. simulation on heat resistance of solar composite wall was carried out, associated with three air flow patterns which refer to stillness, natural convection and forced convection, and compared with common wall without solar panel. It was found that the conditioning load was decreased remarkably due to the wall's reducing heat gain. Besides, the heat resistance was affected by interlayer thickness, the optimum interlayer thickness of different conditions of natural convection was given .

A grid system is a dynamic and distributed environment which contains mass entities and resources, and is involved in large-scale data exchanges and resource sharing. Thus in grid system, information security is a prime concern. Trust mechanism is a main part of grid security. Taking the fuzziness of behavior trust into consideration, this paper introduces fuzzy theory to grid trust and proposes a novel trust model in order to better manage trust relationships between grid entities, presenting the calculation of direct and recommended trust based on fuzzy comprehensive evaluation. Especially, the paper adds the definition mechanism of trust class based on fuzzy cluster analysis to the trust model, achieving dynamic and better visualized definition of trust class. Case study shows that the proposed model can efficiently evaluate entity trust and give clear, accurate judgment upon entities’ trust class, which contributes to the establishment of access control policies.