-statistic is the ratio between a normal (0,1) distributed variable and the square root of a centrally distributed chi-square variable divided by its expected value, i.e., its degree of freedom.

This paper evaluates empirically some very common theories of the freight rate generating process in the time charter markets. After a review of the most common assumptions made of the way time charter rates are set, the hypotheses are identified as follows: (a) the Zannetos Hypothesis, (b), the Lagged Zannetos Hypothesis, (c) the Koyck Lag Hypothesis, (d) the Rational Expectation Hypothesis, and (e) the Conventional Wisdom Hypothesis. These hypotheses are tested using statistical cointegration analysis that includes both an Augmented Dickey-Fuller (ADF), and a Johansen likelihood ratio test. Confronted with the data, hypotheses (a) and (b) are rejected outrightly. In the Koyck Lag case, the ADF statistic seem to confirm the hypothesis. A closer look at the numbers reveals that all of the impact on the time charter rates comes from the lagged dependent variable. Hence, the Koyck Lag Hypothesis is rejected. In the Rational Expectation case, the two tests conflicted. Based on the fact that the Rational Expectation Hypothesis includes the lagged dependent variable and that the Johansen test has been found to be a more robust test than the ADF test, the Rational Expectation Hypothesis is rejected. The fifth hypothesis is a reflection of the general bulk industry perception that the time charter rate is impacted by changes in the comparable spot rate and not much by the spot rate levels. In this case both the ADF and the Johansen test accepted the hypothesis for all markets. Thus, the paper concludes that the conventional market explanation of the time charter freight rate setting process is essentially correct-spot rate changes matter spot rate levels do not.     

Some properties of international maritime statistics

This paper tests two fundamental hypotheses concerning international maritime statistics. The first one deals with the question of stationary of the maritime market statistics. The second hypothesis tested is the assumption that the international maritime statistical time series are not distributed according to a normal of Guassian probability law, but rather belong to the same family of distributions with distinctly different critical parameters. Through well documented statistical methods, the paper concludes that the international freight rates observed on a day to day basis are generated by a random walk process. The paper finds that the shipping industry's conventioal wisdom is essentially correct. ‘Last done’ is as good a forecast of tomorrow's freight rate as any other generated by more sophisticated forecasting methods. Furthermore, freight rates and secondhand tonnage prices fluctuate closely together. The freight rates are generated by stochastic processes fully described by the Paretian family of distributions. The critical parameters of these distribution, the characteristic exponents, are such that the risk conscious ship operator can indeed reduce his exposure to risk by securing a correct set of freight rate contracts.     

Environmental impact assessment of sediment dumping in the southern Baltic Sea using meiofaunal indicators

An experimental sediment dumping was carried out in the southern part of the Mecklenburg Bight in June 2001. Foraminiferans and ostracods from superficial sandy sediment were studied in a time series from before dumping until March 2004 in order to assess changes in associations and recolonization patterns of both groups. Additionally, an area sampling covering the dumping site and its surroundings from 15.5 to 20.7 m water depth made it possible to compare associations inside and outside the dumping area as well as the water depth dependent distribution of foraminiferans and ostracods. Salinity values vary within the high alpha-mesohaline and low polyhaline range. The dominating species are Ammotium cassis (Foraminifera) and Sarsicytheridea bradii (Ostracoda). The diversity is low (Fisher alpha index from 0.4 to 3.2 for foraminiferans and 1.0 to 2.5 for ostracods), but higher within the dumping site samples. These higher values are explainable by input of allochthonous tests and valves representing additional species. After the sediment dumping it took two and a half years to re-establish the total foraminiferan association and the total foraminifer/ostracod ratio within the dumping site. Total foraminiferan abundance increases remarkably with water depth (mean 83 tests in 100 ml) driven by higher nutrient availability and more suitable salinity and temperature values within the zone of the oscillating halocline. The distribution of shallow water species such as Cribroelphidium excavatum, Eucythere argus and Hirschmannia viridis, within the transient water layer A. cassis, Nodulina dentaliniformis, S. bradii and Palmoconcha laevata and below Eggerella scabra indicate the depth position of the halocline. Water depth and sediment dumping influence are the main driving factors for the distribution of foraminifer and ostracod associations within the study area. However, a significant sedimentological difference between samples inside and outside the dumping area is not recognizable.     

Implementation and validation of a three degrees of freedom steering-system model in a full vehicle model

This paper describes the coupling between a three degrees of freedom steering-system model and a multi-body truck model. The steering-system model includes the king-pin geometry to provide the correct feedback torque from the road to the steering-system. The steering-system model is combined with a validated tractor semi-trailer model. An instrumented tractor semi-trailer has been tested on a proving ground and the steering-wheel torque, pitman-arm angle, king-pin angles and drag-link force have been measured during steady-state cornering, a step steer input and a sinusoidal steering input. It is shown that the steering-system model is able to accurately predict the steering-wheel torque for all tests and the vehicle model is accurate for vehicle motions up to a frequency where the lateral acceleration gain is minimum. Even though the vehicle response is not accurate above this frequency, the steering-wheel torque is still represented accurately.     

A summary of findings from the first 25 Ballast Water Treatment Systems evaluated by GESAMP

As part of the preparations for entry into force of the Ballast Water Convention (2004), the International Maritime Organization has initiated a process to evaluate the safety and efficacy of potential technologies for disinfecting ballast water on board ships. Ballast Water Management Systems intended to remove potentially ‘harmful aquatic organisms’ are subjected to a review process, one aspect of which is aimed at ensuring safety by assessing the risks of the systemto the environment, human health (including the ships crew) as well as the safety of the ship. With 25 systems in the various stages of the evaluation process and some already approved, this paper takes a first look at the types of systems under development, especially their environmental characteristics and look for any emerging trends. Quite awide range of different technologies are being developed based on chemical, physicochemical and physical mechanisms. Of these, chlorination by electrolysis in-situ is the most common and indications are that such systems may become even more common.     

Planning the driverless city

ABSTRACT

AV technologies have the potential to transform urban landscapes and existing transport systems and networks. Yet, the utopian imaginary of reduced automobile ownership and a new shared economic future sits in tension with suggestions that car dependency, urban sprawl and transport inaccessibility will be exacerbated. The issues are situated in a complex governance landscape involving an influential private sector who are increasingly setting the agenda. The public sector may be forced into reacting to the new innovations by information technology and automobile companies as they are introduced into existing built environments. Drawing on an extensive literature base and interviews with public sector planners, this paper reveals the conceptual gaps in the framing of AV technology – the prospects and limits – and how these are conceived. The paper raises questions about the role urban planning can play in the rollout of AVs in order to anticipate and mediate unwanted built environment and socio-spatial impacts, as well as reconciling the ambition of transport innovation with the public purpose of planning.     

综合安全评价在船舶动力装置中的应用

综合安全评价（FSA）是一种在工程技术与工程运行管理中用于制定合理可行的规则和提供风险控制的综合性、结构化和系统性的分析方法，将FSA引入到船舶动力装置的安全评价中，是对船舶安全评价的一次尝试，按照综合安全评价的五个步骤对影响船舶动力装置安全的因素进行了分析评价。具体应用时，使用故障树分析法以拉缸故障为实例做了定性和定量分析，根据评价结果提出了相应的安全管理措施，为船舶轮机人员及管理人员提供参考。     

) and annual payments (a) is a follows:

Modern management techniques are slowly but surely being introduced aslo in shipping management. Large sections of the industry practises strategic management at various levels in the firm. This paper outlines a method for deciding chartering strategies in the international bulk shipping industry. A well known risk/return model is tailored to transportation contracts in the shipping industry. The model delineates a set of optimally defined transportation contracts that may serve as a basis for the shipowner's strategic decisions. The strategies and elements of strategies suggested by the model have historically been practised by a number of successful shipowners. An important conclusion of the paper is that no second best problems exists and hence movement towarts the optimal solution is advocated even if such a solution cannot or will not be reached. Additionally, the paper provides an organized way of crafting, analysing and applying chartering strategies where the outcomes can be clearly defined and analysed based on well known statistical concepts and theories.     

多孔沥青混合料堵塞规律离散元仿真

为揭示多孔沥青混合料孔隙堵塞机理,开展了多孔沥青混合料堵塞模型试验与仿真模拟结合研究;基于电子计算机断层扫描与离散元软件PFC3D V5.0分析了多孔沥青混合料孔隙特征,得到了多孔沥青混合料的孔隙数据;在PFC3D V5.0中投放各粒径集料并根据孔隙特征生成压实虚拟试件,以MATLAB切片对比实际试件孔隙图像验证模型准确性;在自重条件下设置特定级配组成堵塞物侵入多孔沥青混合料试件模拟仿真,并以室内试验结果对照验证,改变投放堵塞物粒径,分析了试件孔隙衰变率,找出了堵塞敏感颗粒;在自重条件下引入流体模拟仿真试验,改变了流体渗流速度,分析了试件堵塞变化规律。研究结果表明：PFC3D V5.0生成的虚拟试件具备较高的精确度,仿真揭示了试件堵塞规律,小颗粒除堆积于喉孔处产生堵塞外,还会在嵌挤成型后与大粒径颗粒积聚产生堵塞;自重条件下的堵塞主要集中在混合料试件上层30 mm处,相应堵塞敏感颗粒粒径分布为0.150~0.600 mm,堵塞颗粒粒径分布对堵塞结果影响较大;在重力与流体条件下,随着渗流速度从0.005 m·s^-1增加到0.030 m·s^-1,孔隙衰变率变化速度增加,残留在混合料内部的堵塞物减少,孔隙衰变率减小,排水沥青路面在设计与养护时也需将当地降雨条件带入考虑。     

Range Extender Module Transmission Topology Study

Range extender modules are one option to compensate for short drive ranges of electric vehicles. The close interaction of combustion engine and generator poses new challenges in development. A key requirement for range extender systems is to be light and virtually imperceptible in operation. High-speed electrical machines aim at increasing power density. However, their introduction in a range extender requires a gearbox. The combustion engine torque fluctuations can lead to rattle in the gearbox. The rattle can be overcome by a dual mass flywheel. An interdisciplinary model is developed and used to analyse three different range extender systems: one with a low speed generator without gearbox, one with a high-speed generator, and one with a high-speed generator and a dual mass flywheel. The efficiency was found to be higher for the system with a low speed generator, whereas the power density and the costs are beneficial for the high-speed concept. A dual mass flywheel eliminates the changes of torque direction in the gearbox. It reduces the speed fluctuations of the gearbox and generator by over 90 % compared to the low speed setup. But it increases rolling moment and subsequently chassis excitation compared to a setup with only a gearbox.