Study on State Parameter Control of Intake Air in Utility Tunnels Based on BB-MOPSO北大核心CSCD

In order to explore the control method of the intake air state in utility tunnels when the outside fresh air humidity is too high, taking the ventilation works of a utility tunnel section in Pingtan comprehensive experimental area as the research background, this paper proposes the control method of intake air state parameters for ventilation and dehumidification in utility tunnels under normal and accident conditions, by means of the effective ventilation and dehumidification duration prediction model, the evolutionary multi-objective algorithm (EMOA), and in combination with the ventilation control requirements. The results show that the intake air state parameter controller can be adjusted freely according to the different requirements of decision makers for ventilation fan working duration and dehumidifier working temperature and moisture content, and the optimized appropriate control objectives can be achieved, which is conducive to the real-time decision-making of the intake air state parameter control for ventilation and dehumidification in utility tunnels. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Development of a self-driving car that can handle the adverse weather

Lane and road recognition are essential for self-driving where GPS solution is inaccurate due to the signal block or multipath in an urban environment. Vision based lane or road recognition algorithms have been studied extensively, but they are not robust to changes in weather or illumination due to the characteristic of the sensor. Lidar is a sensor for measuring distance, but it also contains intensity information. The road mark on the road is made to look good with headlight at night by using a special paint with good reflection on the light. With this feature, road marking can be detected with lidar even in the case of changes in illumination due to the rain or shadow. In this paper, we propose equipping autonomous cars with sensor fusion algorithms intended to operate in a different weather conditions. The proposed algorithm was applied to the self-driving car EureCar (KAIST) in order to test its feasibility for real-time use.     

A Practical SSL Server Performance Improvement Algorithm Based on Batch RSA Decryption

The secure socket layer/ transport layer security（SSL/TLS） handshake protocol uses public key cryptographic algorithms such as RSA for key establishment. Typically, public key cryptographic algorithm is computational intensive due to the modular multiplications. Therefore, SSL/TLS servers often become swamped while performing public key decryptions when the simultaneous requests increase quickly. A batch RSA decryption algorithm was proposed. The novel algorithm provides the reasonable response time and optimizes server performance significantly. The decryption speedup is proportional to the batch size b, for instance, the speedup factor is 4, while in Shacham＇s scheme the acceleration rate is only 2.5 when b = 4.     

Simulations of roughness growth on rails - results from a 2D non-Hertzian, non-steady contact model

A new model for simulating rail roughness growth on tangent track is presented in this paper. The model consists of three relatively independent components: (1) a time-domain vehicle/track interaction model; (2) a 2D non-Hertzian and non-steady wheel/rail contact model; and (3) a wear model. Wheel/rail contact forces for a given initial roughness obtained from the vehicle/track interaction model are used by the contact model to calculate the contact patch size, normal pressure and tangential stresses with material removal assumed to be linearly proportional to the friction work in the contact patch. The roughness profile is updated and fed back into vehicle/track interaction model. The 2D contact model is initially compared with a 3D model for various wavelength of initial sinusoidal roughness. Long term roughness growth is then simulated with the 2D contact model. Simulation shows that all initial sinusoidal roughness of wavelengths between 20-100 mm are levelled out. The wavelength-fixing mechanism, that has previously been used to explain the cause of corrugation, is not found in the present investigations.     

The impact of European climate change regulations on international tourist markets

We use a model of international and domestic tourist numbers and flows to investigate the effect of various climate policy instruments implemented in Europe on arrivals and emissions for the countries concerned. We find that these schemes do not fulfil their desired effects. The introduction of aviation into the European trading system results in a fall in the number of tourists travelling into the European Union in favour of other destinations. It also causes a significant welfare loss with only a small reduction in emissions. The flight taxes in the Netherlands and the UK result in different substitution effects across destinations (depending on the zones being taxed) but both policies do have the same consequence of inducing global welfare losses and also reducing visitor numbers to the countries. We find that when these policies are combined their effects are additive. Welfare impacts are robust to variations in the underlying assumptions and changes in the scope of the taxes examined have the expected effects.     

Development of an Operability Evaluation Framework for Remotely Controlled Ground Combat Vehicles in a Simulated Environment

This paper proposes a systematic framework for operability evaluation of remotely controlled ground combat systems (RGCS) in a simulated environment. The popular human-robot interaction metric used in unmanned vehicle systems is called fan-out (FO) and represents the maximum number of robots/vehicles that could be controlled by a single human operator. However, FO is inappropriate for systems with a lower level of automation where vehicles are remotely controlled by a human, such as RGCS. The theoretical background of the suggested framework is based on McRuer’s crossover model that was initially developed in the aviation domain for explaining pilot handling issues. In this study, an evaluation/analysis software prototype was developed, known as the RGCS operability evaluation tool in a simulated environment (ROPES). The ROPES was designed to be a simple tool for use by officers or researchers who only have intuitive understanding on the human adaptability. The ROPES includes two sub-modules; 1) an interactive interface for the configuration of the RGCS dynamic parameters and user interfaces and 2) a time-varying graphical display of system and human performance. Examples case studies demonstrate the advantage of the ROPES, and improvement points were identified for future development.     

Effect of UWS injection at low exhaust gas temperature on NO<Subscript>x</Subscript> removal efficiency of diesel engine

Urea-SCR systems have been widely used in diesel vehicles according to the strengthened NO_x (Nitrogen Oxides) emission standard. The NO_x removal efficiencies of the latest well optimized urea-SCR system are above 90 % at moderate exhaust gas temperature of 250 ~ 450 °C. However, a large amount of NO_x is emitted from diesel vehicles at cold start or urban driving conditions, when the exhaust gas temperature is not high enough for SCR catalyst activation. Although many researchs have been stuied to improve NO_x conversion efficiency at these low temperature conditions, it is still one of important technical issues. In this study, the effect of UWS injection at low exhaust gas temperature conditions is studied. This study uses a 3.4 L diesel engine equipped with a commertial urea SCR system. As a result, it is found that about 5 % of NO_x removal efficiency is improved in the NRTC test when UWS injection starts at the SCR inlet temperature of 150 °C compared to 200 °C. It is also found that urea deposits can be formed on the wall of exhaust pipe, when the local wall temperature is lower than temperature of urea decomposition.     

Mixed Harmonic Runnable Scheduling for Automotive Software on Multi-Core Processors

The performance of automotive electronic control units (ECUs) has improved following the development of multi-core processors. These processors facilitate fast computing performance without increasing clock speed. System developers partition automotive application runnables to have parallelizability and avoid interference between various software modules. To improve the performance of such systems, an efficient scheduler is necessary. In this regard, for multi-core ECUs, the automotive open system architecture (AUTOSAR) suggests partitioned static priority scheduling for parallelized software. In the AUTOSAR approach, clustering and partitioning of runnables for specific cores becomes difficult, but there is no exact criterion followed for partitioning the runnables. Consequently, cores are not balanced against loads, and under contingency conditions, there is a chance that tasks will miss deadlines. In this study, we address this problem by exploring a mixed harmonic runnable scheduling algorithm that includes partitioned scheduling. We tested this algorithm using high load conditions under contingency consequences, and we evaluated it using models of periodic runnables, periodic interrupts, and event-triggered interrupts. The performance parameters considered in this paper are balancing performance and the deadline missing rate. Our results indicate that the proposed algorithm can contribute toward improving the functional safety of vehicles.     

Simulation of wind-driven circulation in the Gulf of Elat (Aqaba)

The Princeton Ocean Model (POM) has been used to investigate the wind-driven circulation in the stratified long and narrow Gulf of Elat (Aqaba). Our results indicate that the circulation consists of a series of gyres aligned along the main axis of the basin, and that their size and location are strongly affected by the shoreline and, to a lesser extent, by the hydrography. The seasonality in both the flow and the free surface height (FSH) at any specific station are caused mainly by the strong seasonality in the hydrography — the FSH and the magnitude of the currents above the thermocline are inversely related to the thickness of the upper layer. The seasonality in the flow is also manifested in the location and diameter of the gyres. This seasonal change in the gyres' diameter and location might provide an explanation for the current reversal observed at the northern tip of the western boundary during the month of February.     

The effects of added transportation capacity on travel: a review of theoretical and empirical results

(Added to the original text) A fundamental solution to the issue of congestion cannot be reached without addressing the question of life-style. This paper reviews the definitions of life-style found in the literature, and identifies variables that have been commonly associated with life-style. Using US consumer expenditure data, life-styles are analyzed longitudinally (examining trends during the 1953–1983 time frame) and cross-sectionally (comparing segments of the population stratified by income, life-cycle stage, and age), and likely relationships to travel behavior are noted. The usefulness of existing empirical findings to long-range forecasting is explored by speculating on shifts of behavioral units across life-style segments, and on shifts in the behavioral patterns within each life-style segment.