Application of genetic algorithms for joint optimization of signal setting parameters and dynamic traffic assignment for the real network data

This paper presents the joint optimization of signal setting parameters and dynamic user equilibrium (DUE) traffic assignment for the congested urban road network. The simulation-based approach is employed to obtain the DUE condition for the case of multiple-origin multiple-destination traffic flows. The dynamic traffic assignment simulation program (DTASP), developed in C language is used to assign the traffic dynamically on the road network, whereas method of successive averages (MSA) is modified and used to arrive at the DUE condition. The artificial intelligence technique of genetic algorithms (GAs) is applied to obtain the optimal signal setting parameters and path flow distribution factor for DUE condition. The methodology developed in such a way that joint optimization of signal setting parameters with DUE is obtained. The proposed method is applied to the real network data of Fort Area of Mumbai city comprising of 17 nodes and 56 unidirectional links with 72 Origin–Destination pairs, where all the 17 nodes are signalized intersections. The traffic flow condition for the optimized signal setting parameters is considerably improved compared to the existing signal settings. The results prove that the GA is an effective technique to solve the joint optimization problem for the real network data.     

Perceptions of foreign exchange rate risk in the shipping industry

This is an analysis of the impact of exchange rate risk on the performance of major shipping companies from two important maritime nations, Japan and Norway. For the shipping industry, such risk is exacerbated by freight rates fixed in US dollars which must then be converted into numerous other currencies. The appreciation of the Yen against the US dollar has been such that Japanese companies have been impelled to insulate themselves from exchange rate movements by natural hedging. For Norway, where fluctuations of the Krone against the US dollar have been less dramatic, exposure has been maintained, allowing an element of speculation. In both cases the market indicates that exchange rate risk is a significant factor in the determination of corporate performance.     

A dynamic model for marginal cost pricing of port infrastructures

ABSTRACT

A dynamic model for marginal cost pricing of port infrastructures links costs to system performance by combining a power-law function with time-dependent queueing analysis. Additionally, the model incorporates the marginal cost of capacity, including the effects of economies of scale. This allows the calculation of the marginal cost price under a dynamic framework. The model accounts for nonlinear behaviour of port demand, which is sensitive to price and service levels. The effects over time of cost and service levels on the port’s operational performance are quantified. The proposed model allows determining the optimal timing for capacity investment. The model is a starting point for the application of marginal cost pricing to ports. However, for practical application of such pricing method it is necessary to apply a system’s approach, as productivity and costs must be assessed at the terminal’s component level. This should allow the derivation of a marginal cost function at the terminal’s component level.     

The Origins and Early Implementation of the Magnuson-Stevens Fishery Conservation and Management Act of 1976

The Magnuson-Stevens Fishery Management and Conservation Act, enacted in 1974, is the primary federal fishery management legislation in the United States. The political impetus that led to enactment was the extensive foreign fish off U.S. shores that expanded following World War II and the failure of international negotiations to prevent the decline in many fisheries relied upon by domestic fishers. In Congress, there was uncertainty as to whether a comprehensive management program would be created along with a unilateral extension of fishery management jurisdiction out to 200 nautical miles. The delay in agreement over a new United Nations Law of the Sea Treaty and resolution of the extent of coastal nation jurisdiction over fisheries culminated in enactment of the legislation sponsored by Senator Warren Magnuson, a Democrat from Washington State, and Senator Ted Stevens, a Republican from the State of Alaska.     

A selection method of offshore production systems considering uncertainties

Journal of Marine Science and Technology - The development of an offshore deepwater oilfield is a complex and risky task. One core problem in this project is the selection of a production system...     

Time-series analysis of remote-sensed chlorophyll and environmental factors in the Santa Monica–San Pedro Basin off Southern California

The time-series of remote-sensed surface chlorophyll concentration measured by SeaWiFS radiometer from September 1997 to December 2001 and the relevant hydrological and meteorological factors (remote-sensed sea surface temperature, atmospheric precipitation, air temperature and wind stress) in Santa Monica Bay and adjacent waters off southern California were analyzed using wavelet and cross-correlation statistical methods. All parameters exhibited evident seasonal patterns of variation. Wavelet analysis revealed salient long-term variations most evident in air temperature during El Niño 1997–1998 and in wind stress during La Niña 1998–1999. Short-period (<100 days) variations of remote-sensed chlorophyll biomass were mostly typical to spring seasons. Chlorophyll biomass was significantly correlated with air temperature and wind stress: an increase of chlorophyll biomass followed with 5–6-day time lag an increase of wind stress accompanied by a simultaneous decrease of air temperature. The mechanism of these variations was an intensification of phytoplankton growth resulting from the mixing of water column by wind stress and entrainment of nutrients into the euphotic layer.     

Observations on colony formation by the cosmopolitan phytoplankton genus Phaeocystis

Few marine phytoplankton have heteromorphic life cycles and also often dominate the ecosystems in which they occur. The class Prymnesiophyceae contains a notable exception: the genus Phaeocystis includes three species that form gelatinous colonies but also occur within their ranges as solitary cells. Phaeocystis antarctica and P. pouchetii are exclusively high latitude taxa, and are notable for regionally tremendous blooms of the colony stage. P. globosa occurs circumglobally, yet its colony blooms primarily are confined to colder waters within its range. Three additional species are warm water forms that have been reported only as solitary cells or loose aggregations that bear little resemblance to the organized colonies of the other taxa. Interpretation of existing data indicates that resource availability (light, temperature and nutrients) by itself is not sufficient to explain this distinction between cold-water colony-forming taxa and warm water solitary cell taxa, nor why colony development in P. globosa is essentially a spatially restricted phenomenon within a much broader geographic range. Colony development by P. globosa in situ has been observed at temperatures ≥20 °C, but only rarely and generally under conditions of seasonally or anthropogenically elevated nutrient supply. Data presented here demonstrate colony development at 20–22 °C in natural plankton communities from oligotrophic waters that were pre-screened through 63 μm mesh (i.e. lacking mesozooplankton and large microzooplankton), but not in unscreened communities containing microzooplankton and >63 μm zooplankton. Reduction of colony proliferation at higher temperatures by mesozooplankton grazing remains as an intriguing possibility that is consistent with available evidence to help explain differences in latitudinal extent of in situ colony development. These data are interpreted within a theoretical framework regarding the potential advantages and disadvantages of the two life cycle stages.     

天然海水中15CDV6/MDN138及15CDV6/MDN250合金的电流相互作用（英文）

The galvanic corrosion behavior of the metal combinations 15 CDV6/MDN138 and 15 CDV6/MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250, and 15 CDV6 of the individual metal, the galvanic potential and galvanic current of the couples 15 CDV6/MDN138 and 15 CDV6/MDN250, were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with 15 CDV6 were analyzed using XRD. The electrochemical behavior of MDN138, MDN250, and 15 CDV6 in seawater was studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with 15 CDV6 have been examined with a scanning electron microscope. The results of the study reveal that the galvanic protection offered by15 CDV6 to MDN250 and MDN138 in natural seawater amounts to 93% and 98%, respectively, implying that the galvanic protection offered by 15 CDV6 is continuous and effective, which has been further evinced from the adherent nature of the calcareous deposit film comprising compounds such as CaCO_3(calcite, aragonite, and vaterite), MgCO_3(magnesite),Mg(OH)_2(brucite), and MgO(brucite).     

Recreational Leasing of Alaska Commercial Halibut Quota: The Early Years of the GAF Program in Alaska

The Pacific Halibut Catch Sharing Plan formalized the process for allocating halibut between the Alaska commercial and recreational charter sectors. It included a new program intended to allow for “flexibility” through inter-sectoral trading, permitting charter operators to lease commercial halibut pounds to relax client harvest restrictions. Here we evaluate the first two years of lease market activity and participation. Participation from some commercial quota holders in the lease market suggests that the program provided beneficial flexibility; in fact, the number of transfers to the charter sector was greater than transfers within the commercial sector for some quota types. We also identified a high proportion of self-leasers. However, transfers to the charter sector were on average smaller than within-sector commercial transfers, and total poundage leased by the charter sector was low compared with commercial transfers. Usage of leased quota by the recreational charter sector enables the harvest of larger fish or additional fish, and provides flexibility in catch composition on halibut closure days. Finally, the value-per-pound may be higher in the charter sector, as commercial-to-charter transfer prices approached the commercial ex-vessel price.