Risk and return of U.S. water transportation stocks over time and over bull and bear market conditions

The aim of this paper is to investigate the behaviour of water transportation company stock returns in the U.S. stock exchanges from 1985 to 1994 in order to determine whether the systematic risk of this industry is different from that of the 'average' company in the market, whether it has changed over the ten year period, over bull and bear market conditions, and whether there is a firm 'size' effect in the industry. In the context of the Capital Asset Pricing Model (Capm), we find that the systematic risk of the shipping industry return is not different from that of the 'average' company. It is also found that the covariance of water transportation companies with respect to the overall stock market return did not change over the ten year period although it appears that it has changed over normal upward/downward market movements. There is also reasonable evidence that the intercept of the equation might have changed over normal upward/downward market movements. Finally, we document contradictory evidence regarding the size effect; during the period 1985-1989 we find small companies to have significantly higher returns and risk while during the period 1990-1994 medium size companies tend to have higher risk than small and large firms, which is not however compensated by higher returns.     

Coastal management issues for the mouth of the river murray,South Australia

Abstract

This paper examines the management issues relating to the potential closure of the mouth of Australia's largest river. The importance of maintaining the river mouth is outlined, together with the implications of restricted river flow and the management response following the most recent closure of the mouth in 1981. One of the major unresolved issues is the question of responsibility and funding, which has arisen because of overlapping jurisdictions on either side of the river mouth and a lack of jurisdiction f or the mouth itself, which is an administrative boundary.     

高速改扩建预应力T梁拼宽结构分析

中小跨径预应力拼宽T梁桥是高速改扩建的主要桥型,依托福州至厦门高速公路改扩建项目,采用结构空间有限元法分析了拼宽后T梁拼接部位的受力状况,得出T梁桥拼宽新桥沉降差值宜控制在5mm以内和新、旧T梁间增置横隔板能有效改善接缝处受力的结论。     

Model-based control system design in a urea-SCR aftertreatment system based on NH3 sensor feedback

This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment system based on NH₃ sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with design based on a sliding mode control framework. The control system based on NH₃ sensor feedback is analyzed via simulation by comparing it to a control system developed based on NO_x sensor feedback. Simulation results show that the NH₃ sensor-based strategy performs very similarly in comparison to a NO_x sensor-based strategy. The control system performance metrics for NO_x index, urea index, urea usage, and NH₃ slip suggest that the NO_x sensor can be a potential alternative to a NO_x sensor for urea-SCR control applications.     

Optimal scheduling of the flexray static segment based on two-dimensional bin-packing algorithm

FlexRay is a reliable and hard real-time in-vehicle communication protocol that is strongly promoted by car manufacturers as the de facto standard in the automotive domain. The protocol offers both a time-triggered and an eventtriggered architecture. This paper focuses on the optimal scheduling of the time-triggered component of FlexRay known as the static (ST) segment using a two-dimensional bin-packing technique. To maximize the bandwidth utilization in the ST segment, a fast heuristic as well as an efficient integer linear programming approach are proposed. Our methods directly schedule signals into slots including frame packing, according to signal-based data scheduling and the slot/ cycle multiplexing mechanisms presented by the latest version of the FlexRay protocol. The benefits of our proposed methods are demonstrated by extensive experiments on synthetic and an automotive X-by-wire system case study. An additional test case is examined to emphasize the superior performance of the proposed approach relative to that of existing optimal scheduling approaches.     

工厂火灾,爆炸场所危险度综合评价法

为减少火灾事故，介绍了“工厂火灾、爆炸场所危险度综合评价法”，“道氏法”是该法的基础。分析了“道氏法”的不足，而提出了固定危险和现实补偿的综合性计算方法。还通过实例记述了新方法的优点、基本原理和应用方法。该法能用于评价工厂企业危险设备、装置与场所的火灾、爆炸危险程度。     

Crash protection of Hybrid Electrical Vehicles for amending the KMVSS No. 91

This paper explores issues related to the electrical safety of Hybrid Electrical Vehicles (HEVs) during and after various crash events. Japanese and American federal regulations regarding occupant protection against high voltages in Electric Vehicles (EVs) and HEVs were surveyed and analyzed in this study. Front, side and rear impact tests for two types of HEVs were conducted to investigate electrolyte spillage, the retention of the propulsion battery system and the electrical isolation of the occupant. The test results met the related criteria. The test procedures and the criteria for occupant protection established through this study were amended to Korean Motor Vehicle Safety Standard (KMVSS) No. 91 to add the crash protection of the EVs and the HEVs.     

Comparison of the optimum designs of center pillar assembly of an auto-body between conventional steel and ahss with a simplified side impact analysis

This study compares the optimum designs of center pillar assembly with advanced high-strength steel (AHSS) to that of conventional steel for crashworthiness and weight reduction in side impacts. A simplified side impact analysis method was used to simulate the crash behavior of the center pillar assembly with efficient computing time. Thickness optimization aims to perform an S-shaped deformation of the center pillar toward the cabin to reduce the injury level of a driver in a crash test. Center pillar members were regarded as an assembly of parts that are fabricated with tailor-welded blanks, and the thickness of each part was selected as a design variable. The thickness variables of parts that have significant effects on the deformation mechanism were extracted as the main design variables for thickness optimization based on the results of a sensitivity analysis with design of experiments. The optimization condition was constructed to induce an S-shaped deformation mode and reduce the weight of the center pillar assembly. An optimum design was obtained after several iterations with response surface methodology (RSM). Optimization was first performed with conventional steel and then with AHSS with the same procedure to optimize the crashworthiness of the center pillar assembly. After thickness optimization, optimum designs were applied to the full vehicle analysis to evaluate the validity of the optimization scheme with the simplified side impact analysis method. Then, the crashworthiness of optimum designs with conventional steel and AHSS were compared using the full vehicle analysis. This comparison demonstrates that AHSS can be more effectively utilized than conventional steel to obtain a lightweight design of an auto-body with enhanced crashworthiness.