Why is the southwest the most productive region of the East Sea/Sea of Japan?

The East Sea/Sea of Japan is a moderately productive sea that supports a wealth of living marine resources. Of the East Sea subregions, the southwest has the highest productivity. Various authors have proposed coastal upwelling, the Tsushima Current, the Changjiang Dilute Water, eddies, or discharge from the Nagdong River as potential sources of additional nutrients. In this paper, we propose, using satellite data from 1998 to 2006, that the biological productivity of the southwestern region is enhanced mainly by wind-driven upwelling along the Korean coast. Firstly, the climatology of seasonal patterns suggests that the enhanced chlorophyll a along the Korean coast is of local origin. Secondly, coastal upwelling is frequent in all seasons except winter. For example, along the coast of the Ulgi region, enhanced chlorophyll a due to coastal upwelling was observed for 25–92% of the time between Jun and Sep in the period 1998–2006. Thirdly, the advection of upwelled water through various pathways to the deeper basin was observed. Fourthly, there appeared to be a strong correlation between the interannual chlorophyll a variations of the coastal upwelling regions and the Ulleung Basin. The chlorophyll a patterns of both regions were closely related to the wind pattern in the upwelling regions, but not to that in the Ulleung Basin. Finally, changes in advection pathways also appeared to affect the productivity of the Ulleung Basin. Since 2004, there has been a shift in the pathways of upwelled water, and consequent increases in chlorophyll a in the Ulleung Basin were observed. This last observation requires further investigation.     

Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals

Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder ( 50 Sv, 1 Sv = 10⁶ m³ s^− 1) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25 km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600 m; 56°S, 78°E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58°S) and the Antarctic Divergence (64°S) in the eastern Enderby Basin, toward the Australian–Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1 °C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard Island. Further analysis of different supplementary data reveals a complex circulation pattern in the entire Enderby Basin, with several distinctive branches of flow being strongly controlled by prominent topographic features such as the Southwest Indian Ridge, Conrad Rise, Elan Bank, and Kerguelen Plateau. This newly emerged frontal structure refines considerably previous large-scale circulation schematics of the area.     

A study of vibration and vibration control of ship structures

This paper examines the vibration characteristics and vibration control of complex ship structures. It is shown that input mobilities of a ship structure at engine supports, due to out-of-plane force or bending moment excitations, are governed by the flexural stiffness of the engine supports. The frequency averaged input mobilities of the ship structure, due to such excitations, can be represented by those of the corresponding infinite beam. The torsional moment input mobility at the engine support can be estimated from the torsional response of the engine bed section under direct excitation. It is found that the inclusion of ship hull and deck plates in the ship structure model has little effect on the frequency-averaged response of the ship structure. This study also shows that vibration propagation in complex ship structures at low frequencies can be attenuated by imposing irregularities to the ring frame locations in ships. Vibration responses of ship structures due to machinery excitations at higher frequencies can be controlled by structural modifications of the local supporting structures such as engine beds in ships.     

Motorway signals and the detection of incidents

A mathematical model of automobile trip tours is presented. Within a framework of eight common restrictions on automobile trip making, all travel behavior is assumed random and all of the ways in which tours can be arranged are assumed equally likely. Three probability distributions are derived from the model: (1) the probability that a household makes a given number of tours in a day; (2) the probability that a household makes a given number of trips in a day; and (3) the probability that a tour reaches a given number of destinations. It is shown that the model agrees with similar probability distributions generated from home‐interview data for Milwaukee.     

Optimization of transport investment and pricing policies: the role of transport pricing in network design

This paper investigates the role of transport pricing in network design and describes two facts about flow pattern in a transportation system. The first, illustrated by an example of Braess paradox, is that adding a new link to the network does not necessarily minimize the total travel time. The second is that introducing of appropriate toll pricing may reduce not only the total network time but also the travel time for each individual traveller. It follows with the investigations of different system objectives and different pricing policies (only toll pricing and distance‐based pricing are considered), and shows how they affect the system performance and flow pattern. Lastly, a systematic optimization process is proposed for integrated planning of transport network and pricing policies.     

A new efficient EDI system for container cargo logistics

There have been many efforts to develop a logistics information system in the Korean logistics industry. In spite of these efforts, there are many points which need improvement in the Logistics Information System, of which function is the electronic data communication without added value. This paper aims to describe some of the main problems and the successful factors which are being found in the evolution of the present EDI systems for clearing import/export container cargoes, with special reference to Singapore, Korea, and Japan. Following this, leaving legal issues aside, to suggest workable guidelines for designing a new efficient EDI system for container cargo logistics. As a result of the review, the following successful factors are drawn: (a) the planning, requirement analysis and design of EDI are critical, as it provides a framework for its implementation; (b) as the data of customs clearance are an integral part of a logistics EDI system, the inclusion of customs in the system design is essential; (c) the sharing system of cargo data as the framework of the logistics EDI is efficient for data interchange; (d) the EDI software for the user has been developed and provided by an EDI network operating company; and (e) to facilitate communication between trading partners and the transport sector, it is necessary to adopt a global message standard, such as EDIFACT.     

Commentaries

Abstract

This paper surveys the technologies available for constructing a pervasive, national‐scale road pricing system. It defines the different types of road pricing, the methods by which a vehicle’s position can be determined, and then examines possible pricing regimes in the context of their technological requirements and implications. The issue of enforcement and the distribution of pricing policies are considered, and further complexities are outlined. An examination of the security aspects of such systems is made, focusing particularly on the need to ensure privacy using technological, rather than solely procedural, methods. The survey concludes that a pervasive, national‐scale deployment is unlikely to be technically achievable in the short‐term.     

Estimates of vertical mixing during a Lagrangian experiment off the Galician coast

An adjoint 1-D model was used to determine vertical diffusivity coefficients from temperature profiles collected within a filament escaping from the Galician coast following an upwelling event. The optimisation scheme ended with relatively high diffusivity values within the thermocline (9×10⁻⁵ m² s⁻¹). Such high values are relevant for biogeochemical exchanges between surface and deep waters in stratified areas.The optimised values were several orders of magnitude higher than the bulk of diffusivity measurements recorded with a free-falling device; however, the optimisation solution was consistent with the arithmetic mean of the measurements in the thermocline (7.7×10⁻⁵ m² s⁻¹), giving more weight to the few largest values. Below the thermocline, the data assimilation method failed because of the three-dimensional nature of the advective field of the upwelling system. Ignoring this advective forcing in the model led to estimates that were two orders of magnitude too high.The results suggest that turbulent mixing is a random process where a few intense events determine the average mixing that drives the long-term evolution of the water column structure. This statistical property is very important when one wants to use instantaneous diffusivity measurements for modelling purposes.     

Short-term Hourly Traffic Forecasts using Hong Kong Annual Traffic Census

The need for acquiring the current-year traffic data is a problem for transport planners since such data may not be available for on-going transport studies. A method is proposed in this paper to predict hourly traffic flows up to and into the near future, using historical data collected from the Hong Kong Annual Traffic Census (ATC). Two parametric and two non-parametric models have been employed and evaluated in this study. The results show that the non-parametric models (Non-Parametric Regression (NPR) and Gaussian Maximum Likelihood (GML)) were more promising for predicting hourly traffic flows at the selected ATC station. Further analysis encompassing 87 ATC stations revealed that the NPR is likely to react to unexpected changes more effectively than the GML method, while the GML model performs better under steady traffic flows. Taking into consideration the dynamic nature of the common traffic patterns in Hong Kong and the advantages/disadvantages of the various models, the NPR model is recommended for predicting the hourly traffic flows in that region.     

Dual extended Kalman filter for vehicle state and parameter estimation

The article demonstrates the implementation of a model-based vehicle estimator, which can be used for combined estimation of vehicle states and parameters. The estimator is realised using the dual extended Kalman filter (DEKF) technique, which makes use of two Kalman filters running in parallel, thus 'splitting' the state and parameter estimation problems. Note that the two problems cannot be entirely separated due to their inherent interdependencies. This technique provides several advantages, such as the possibility to switch off the parameter estimator, once a sufficiently good set of estimates has been obtained. The estimator is based on a four-wheel vehicle model with four degrees of freedom, which accommodates the dominant modes only, and is designed to make use of several interchangeable tyre models. The paper demonstrates the appropriateness of the DEKF. Results to date indicate that this is an effective approach, which is considered to be of potential benefit to the automotive industry.