Performance Comparison of Automated Vehicle Controllers

１IntroductionAutomatedhighwaysystems穴AHS雪havedrawnmoreandmoreattentioninrecentyearsbecausefullautomationcangreatlyincreasehighwaycapacitywhileimprovingsafety．IneachplatoonofAHS熏everyvehicle穴excepttheleadingcar雪tightlyfollowstheprecedingvehicle熏andcanreactquicklytotheprecedingcarandemergency．Thedesignofintelligentvehiclecontrolsystemisanim鄄portantpartofAHS熏anditinvolvesautomaticcontrolofthrottleandbrake眼１演．Oneoftheobjectivesofintelligentvehiclecontrolistoachieveautomaticvehic…     

Autonomous driving control for ITS by using learning automaton network with multiple environments

In this paper, the application of the learning automaton (LA) network with multiple environments is proposed for the adaptive controller for ITS autonomous driving. The LA network, which we introduced previously, has the ability to learn which deals with both multiple reinforcement signals and information of multiple environments at the same time. This feature is found to be useful for improving the response of adaptation in dynamic environments such as highways. In order to evaluate the practical advantage of using the network, we designed a simulational highway system, constructed an autonomous travel controller using the simple LA and the LA network, and executed comparative experiments evaluating the performance of adaptation response and collision avoidance. The results show that the performance of the LA network with multiple environments is superior to that using simple LA application with regard to stability and safety. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 150(4): 36–43, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10363     

热处理对Bi变质AHS铝合金组织及力学性能的影响

研究了热处理对Bi变质AHS合金组织及性能的影响.结果表明:AHS合金经Bi变质后,共晶硅组织形貌发生明显变化,由未变质时细长杆状、针片状转变成细小的蠕虫状、纤维状和颗粒状.当Bi含量为4％时,热处理后合金的抗拉强度和伸长率均达到最大值,分别为318 MPa和3.2％.与热处理后未变质合金的抗拉强度和伸长率相比,分别提...     

智能化交通系统的发展现状及未来

20世纪80年代以来，世界一些发达国家纷纷投入智能交通系统(ITS)的研究与开发，并已形成21世纪交通运输系统的发展方向。我国是一个发展中国家，随着经济的高速发展，城市化、汽车化急速发展，导致交通拥挤、事故增多、环境污染等问题日益恶化。针对我国的实际情况，对发展ITS的必要性、紧迫性进行分析，并对发展我国ITS的框架提出了设想。     

应用离散余弦变换的去谐波扫描技术

通常在处理环节消除可控震源产生的谐波干扰会对有效信号产生不良影响;而去谐波扫描技术将这一过程提前到激发阶段,即通过改造原设计信号,实现在激发过程中使输出的谐波噪声最小,从而提高输出信号的精度和信噪比.现有去谐波扫描技术中,硬件方面主要通过对重锤信号与平板信号非线性二次拟合求取改正量实时控制伺服阀,以提高响应精度减少畸变...     

Characterization and grouping of aquatic fulvic acids isolated from clear-water rivers and lakes in Japan

Characteristics of aquatic fulvic acids (FAs) from 10 clear waters in Japan (around the temperate zone) were revealed by several analytical techniques—high performance size exclusion chromatography (HPSEC), elemental analysis, liquid-state ¹³C NMR spectroscopy, isotopic analyses (δ¹³C and δ¹⁵N), and compared with those of International Humic Substances Society (IHSS) standard samples including FAs from brown waters (Suwannee, Pony, and Nordic FAs). Generally clear-water FAs were different from brown-water FAs in chemical properties. Weight-average molecular weights (Mw) of the clear-water FAs were similar to each other, whereas their elemental compositions and carbon species distribution were different. The clear-water FAs all exhibited a high proportion of alkyl carbons, which may be attributed to microbial activity. δ¹³C and δ¹⁵N values of the FAs indicated that there would be a huge gap between origin and chemical structure of clear-water FA. Results of the chemical structural analyses described above were not always linked to those of the isotopic analyses (δ¹³C and δ¹⁵N). Multivariate statistical analysis, i.e. cluster and principal component analysis was applied to reveal differences or similarities in a more objective manner. The FAs were always classified into two clear-water groups and one brown-water group. Aryl-C and O-Alkyl-C contents were important for the grouping. We speculate that the grouping might depend on the differences of aquatic microbial activity caused by the differences of residence time of water.     

Monitoring yield and fruit quality parameters in open-canopy tree crops under water stress. Implications for ASTER

Work on water stress detection at tree and orchard levels using a high-spatial airborne thermal sensor is presented, showing its connection with yield and some fruit quality indicators in olive and peach commercial orchards under different irrigation regimes. Two airborne campaigns were conducted with the Airborne Hyperspectral Scanner (AHS) over olive and peach orchards located in Córdoba, southern Spain. The AHS sensor was flown at three different times on 25 July 2004 and 16 July 2005, collecting 2 m spatial resolution imagery in 80 spectral bands in the 0.43-12.5 μm spectral range. Thermal bands were assessed for the retrieval of land surface temperature using the split-window algorithm and TES (Temperature-Emissivity-Separation) method, separating pure crowns from shadows and sunlit soil pixels using the reflectance bands. Stem water potential and stomatal conductance were measured on selected trees at the time of airborne flights over the orchards. Tree fruit yield and quality parameters such as oil, weight and water content (for the olive trees), and fruit volume and weight (for the peach trees) were obtained at harvest and through laboratory analysis. Relationships between airborne-estimated crown temperature minus air temperature and stem water potential yielded r² = 0.5 (12:30 GMT) at the olive tree level, and r² = 0.81 (9:00 GMT) at the treatment level in peach trees. These results demonstrate that water stress can be detected at the crown level even under the usual water management conditions of commercial orchards. Regressions of yield and fruit quality against remote sensing estimates of crown temperature as an indicator of water stress, yielded r² = 0.95 (olive fruit water content) and r² = 0.94 (peach fruit mean diameter). These results suggest that high-spatial remote sensing thermal imagery has potential as an indicator of some fruit quality parameters for crop field segmentation and irrigation management purposes. A simulation study using ASTER spectral bands and aggregated pixels for stress detection as a function of irrigation level was conducted in order to study the applicability of medium resolution thermal sensors for the global monitoring of open-canopy tree crops. The determination coefficients obtained between the ASTER-simulated canopy temperature minus air temperature and stem water potential yielded r² = 0.58 (12:30 GMT) for olive trees, suggesting the potential for extrapolating these methods to ASTER satellite for global monitoring of open tree canopies.     

基于微机械惯性器件和磁强计的姿态航向系统

给出了一种基于微机械惯性器件和磁强计的姿态航向系统的设计方案,介绍了该系统的算法,并给出了该系统的硬件原理框图和软件流程图。与传统装置相比,该系统具有体积小、重量轻、功耗低、成本低、长寿命等优点。     

一种基于HTTP自适应流的混合码率自适应算法

码率自适应算法是HTTP自适应流技术的热点和难点。提出一种综合网络带宽和缓存两个因素的终端码率自适应算法(Combined with Bandwidth and Buffer,CBB)。该算法采用“探测”的机制在应用层上估算网络实时带宽,避免视频码率频繁切换;然后构建随缓存状态动态变化的平滑因子模型,并基于指数加权移动平均(EWMA)实现带宽的平滑处理;利用推动缓存趋近均衡级别变化的调度策略,尽可能使缓存区的数据量处于均衡的范围。整个算法经带宽估算、平滑处理、量化及确定调度时间构成一个循环作用的闭环。在使用MPEG-DASH标准的参考平台libdash上验证该算法的性能,结果表明,在变化的网络状况中所提算法表现良好。