Human Error in Autonomous Underwater Vehicle Deployment: A System Dynamics Approach

The use of autonomous underwater vehicles (AUVs) for various applications have grown with maturing technology and improved accessibility. The deployment of AUVs for under-ice marine science research in the Antarctic is one such example. However, a higher risk of AUV loss is present during such endeavors due to the extremities in the Antarctic. A thorough analysis of risks is therefore crucial for formulating effective risk control policies and achieving a lower risk of loss. Existing risk analysis approaches focused predominantly on the technical aspects, as well as identifying static cause and effect relationships in the chain of events leading to AUV loss. Comparatively, the complex interrelationships between risk variables and other aspects of risk such as human errors have received much lesser attention. In this article, a systems-based risk analysis framework facilitated by system dynamics methodology is proposed to overcome existing shortfalls. To demonstrate usefulness of the framework, it is applied on an actual AUV program to examine the occurrence of human error during Antarctic deployment. Simulation of the resultant risk model showed an overall decline in human error incident rate with the increase in experience of the AUV team. Scenario analysis based on the example provided policy recommendations in areas of training, practice runs, recruitment policy, and setting of risk tolerance level. The proposed risk analysis framework is pragmatically useful for risk analysis of future AUV programs to ensure the sustainability of operations, facilitating both better control and monitoring of risk.     

Effect of pavement and water deficit on biomass allocation and whole-tree transpiration in two contrasting urban tree species

Urban Ecosystems - Aiming to explore the species-specific responses of biomass allocation and whole-tree transpiration in urban trees to pavement and drought, a field manipulation experiment grew...     

考虑实时预倒箱的出口箱堆场多场桥调度优化

在出口集装箱堆场的实际作业过程中，倒箱是制约场桥作业效率的瓶颈之一。为提高出口箱堆场的作业效能，减少船舶装船作业时间，采用实时预倒来降低倒箱的影响，研究出口箱堆场多场桥调度优化问题。考虑待提箱作业次序固定、场桥间保持安全距离及不可跨越的现实约束，兼顾内集卡的等待上限，侧重场桥作业过程中的实时预倒箱，构建了以带惩罚因子的内集卡总等待时间最少为目标的混合整数线性规划模型。基于问题自身的特点设计了混合和声模拟退火算法，得出了各场桥的行走路径与实时预倒箱方案。在算例实验中，通过与不考虑实时预倒箱的方案、FCFS方案以及下界进行对比，验证了考虑实时预倒箱的场桥调度模型及算法的有效性，为集装箱码头出口箱堆场的场桥调度提供参考。     

Rank aggregation using latent-scale distance-based models

Rank aggregation aims at combining rankings of a set of items assigned by a sample of rankers to generate a consensus ranking. A typical solution is to adopt a distance-based approach to minimize the sum of the distances to the observed rankings. However, this simple sum may not be appropriate when the quality of rankers varies. This happens when rankers with different backgrounds may have different cognitive levels of examining the items. In this paper, we develop a new distance-based model by allowing different weights for different rankers. Under this model, the weight associated with a ranker is used to measure his/her cognitive level of ranking of the items, and these weights are unobserved and exponentially distributed. Maximum likelihood method is used for model estimation. Extensions to the cases of incomplete rankings and mixture modeling are also discussed. Empirical applications demonstrate that the proposed model produces better rank aggregation than those generated by Borda and the unweighted distance-based models.

     

吕氏集团对汉初岭南政策的两次调整

关于吕氏集团执政期间汉朝与南越国的矛盾冲突,传统研究多集中于吕后及其称制时期,而忽视了对事件整体性的把握,即未从吕氏集团执政的全过程加以审视。事实上,吕氏集团对南越国的政策存在两次重要调整,一是吕后时期从怀柔转向对抗,二是"诸吕"时期从南征转为罢兵。吕氏集团的第一次调整只是对原有政策的过激推行,第二次调整则可能是缓和双方关系的一种尝试。但前者不顾客观现实而冒险行事,后者缺乏后续措施而加剧了危机。因此,虽然吕氏集团的两次政策调整均出于巩固政权的需要,但其冒进与盲动的行为只能导致汉朝南部藩属体系陷入空前的危机之中。     

致密碳酸盐岩气藏转向酸酸压技术研究

在分析大牛地气田低渗致密碳酸盐岩储层地质特征的基础上，针对储层改造现状和改造难点提出了转向酸酸压技术。从理论和实验两方面分析了转向酸体系的转向机理，通过流变性能、酸岩反应动力学、转向性能及破胶性能实验分析了转向酸体系的综合性能，最后在A 井试验应用了转向酸酸压工艺，取得了大牛地气田碳酸盐岩储层勘探开发的突破。     

Risk‐Cost‐Benefit Analysis for Transportation Corridors with Interval Uncertainties of Heterogeneous Data

Access management, which systematically limits opportunities for egress and ingress of vehicles to highway lanes, is critical to protect trillions of dollars of current investment in transportation. This article addresses allocating resources for access management with incomplete and partially relevant data on crash rates, travel speeds, and other factors. While access management can be effective to avoid crashes, reduce travel times, and increase route capacities, the literature suggests a need for performance metrics to guide investments in resource allocation across large corridor networks and several time horizons. In this article, we describe a quantitative decision model to support an access management program via risk‐cost‐benefit analysis under data uncertainties from diverse sources of data and expertise. The approach quantifies potential benefits, including safety improvement and travel time savings, and costs of access management through functional relationships of input parameters including crash rates, corridor access point densities, and traffic volumes. Parameter uncertainties, which vary across locales and experts, are addressed via numerical interval analyses. This approach is demonstrated at several geographic scales across 7,000 kilometers of highways in a geographic region and several subregions. The demonstration prioritizes route segments that would benefit from risk management, including (i) additional data or elicitation, (ii) right‐of‐way purchases, (iii) restriction or closing of access points, (iv) new alignments, (v) developer proffers, and (vi) etc. The approach ought to be of wide interest to analysts, planners, policymakers, and stakeholders who rely on heterogeneous data and expertise for risk management.     

汉斯·摩根索的“国家利益”概念探究

"国家利益"概念是摩根索政治现实主义理论的核心概念,它被视为难以捉摸的概念。摩根索关于"国家利益"的观点,可以放在弗里德里希·迈内克的"国家理由"观念的视野中来解读。从摩根索论及"国家利益"的文本中,可以发现理解摩根索"国家利益"观的门径。对这些文本的研究表明:摩根索赋予"国家利益"概念理论与实践双重功能;"国家利益"的构成要素包含相对永恒的要素与可变要素,以及物质性要素与非物质性要素。此外,摩根索的"国家利益"概念具有合理性、道德性与非排他性。重要的是,摩根索不否认"国家利益"包含国家追求的诸如自由、繁荣等终极目标,但是为了应对道德价值演变成意识形态的情势,他认为有必要暂时不涉及国家追求的终极目标。     

空间正义之维的新时代城市治理

习近平总书记明确指出,城市治理是推进国家治理体系和治理能力现代化的重要内容,城市治理的核心目标是维护空间正义;新时代城市治理以促进空间产品分配正义为基点,在对空间环境和社会关系的治理中建设美好美丽的空间场所以维护人民群众的发展正义;以党的十九届四中全会关于国家治理体系和治理能力现代化的新要求为指导,探索新时代城市治理的过程机制和方式方法,切实推进人民群众的空间分配正义、空间协商正义和空间关系正义.