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31.
The responsibility for managing coral reefs and other coastal resources was largely devolved to coastal municipalities and cities in the Philippines in 1991 with the passage of the Local Government Code. Devolution of powers and responsibilities to local government has paved the way for mainstreaming coastal resource management at the local level. However, the capacity to carry out this mandate has only recently begun to mature as municipalities and cities gain an increased awareness of the importance of coastal resources to communities and economic development. Approaches and strategies to increase local government capacity for coastal resource management are described based on the experiences of the Coastal Resource Management Project of the United States Agency for International Development. Qualitative and quantitative data are used to illustrate the possible impact of these capacity building efforts and to describe the current capacity of local government to undertake coastal resource management. After five years of project implementation, coastal municipalities have increased technical capacity, have allotted financial resources, and have achieved key performance benchmarks in the delivery of coastal resource management as a basic service. 相似文献
32.
This paper proposes the adoption of an integrated inventory and transportation system (IITS) to minimize the total costs of inventory and transportation. A non-linear programing is developed by analyzing transportation and inventory costs with one supplier and many retailers in the distribution environment. The paper compares the proposed model with the traditional approach in computing total costs with numerical data. The results indicate that the total costs can be optimized by adopting integrated programing rather than the traditional approach, along with achieving improved customer service levels. In particular, sensitivity analysis is applied to determine the performance of the IITS under various transportation costs, holding costs and shortage costs. It shows that the transportation cost per unit is most sensitive in the proposed model. In this situation, the IITS is more effective for cost saving when set-up cost, holding and shortage costs are high, but is less effective for situations involving high per-unit transportation costs. 相似文献
33.
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. 相似文献
34.
Should we abandon activity type analysis? Redefining activities by their salient attributes 总被引:3,自引:0,他引:3
Sean T. Doherty 《Transportation》2006,33(6):517-536
This paper poses a challenge and begins a search. The challenge is to reconsider the usefulness of traditional activity types (“work”, “shopping”, etc.) in the understanding and modelling of travel behaviour. The search is for the more salient attributes of activities that may serve to better explain complex travel behaviours—such as activity scheduling and tour formation. In particular, this paper focuses on explicit measures of the spatial, temporal and interpersonal flexibility of activities, along with several traditional attributes (frequency, duration, involved persons, travel time, and location). Data from a recent in-depth week-long activity scheduling survey was used to define and compare these attributes. Results show that considerable variability in the attributes between and within traditional activity groups is evident. This casts considerable uncertainty on assumptions that statically assign levels of spatial, temporal, and interpersonal flexibility to any given activity type. A Principal Components Analysis further revealed eight new distinct clusters of activities that share like attributes. The relative role of each attribute in each component is examined, and subjective interpretations emerged (e.g., “Long and frequent”, “Space and time flexible” “Social networking”). The implications of these results for future model development and research are discussed. Future research should continue to expand the search for salient attributes and link them more directly to decision processes. 相似文献
35.
T. A. Wenzel K. J. Burnham M. V. Blundell R. A. Williams 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(2):153-171
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. 相似文献
36.
Yunyoung?Kim Koji?GotohEmail author Masahiro?Toyosada 《Journal of Marine Science and Technology》2004,9(2):70-79
This article considers microgenetic algorithms (GAs), which explore in a small population with a few genetic operators, for cutting-path optimization problems. The major difference between GAs and simple genetic algorithms (SGAs) is how to make a reproductive plan for an improved searching technique because of population choice. It is shown that GAs implementation reaches the near-optimal region much earlier than the SGAs approach, and the GAs give a better solution than simulated annealing (SA). The main objective was to determine what temperature distribution can be obtained from the solution of a travelling distributed heat source. The solution of the travelling heat source on nested raw plate provides information about the vertices of each nested part of the raw plate. From the fact that the initial temperature at a piercing point strongly depends on the heat flow which stems from the previous cutting contour, the temperature of all piercing points must be lower than the critical temperature after each cutting of the components of a part. The critical temperature is identified as the mechanical melting temperature of steels. A heuristic back-tracking method is introduced to find the near-optimum cutting path considering the minimum heat effect on deformation. The heuristic back-tracking method is incorporated with the GAs. 相似文献
37.
The transient elastic deformation of a pontoon-type very large floating structure (VLFS) caused by the landing and take-off of an airplane is computed by the time-domain mode-expansion method. The memory effects in hydrodynamic forces are taken into account, and great care is paid to numerical accuracy in evaluating all the coefficients appearing in the simultaneous differential equations for the elastic motion of a VLFS. The time-histories of the imparted force and the position and velocity of an airplane during landing and take-off are modeled with data from a Boeing 747-400 jumbo jet. Simulation results are shown of 3-D structural waves on a VLFS and the associated unsteady drag force on an airplane, which is of engineering importance, particularly during take-off. The results for landing show that the airplane moves faster than the structural waves generated in the early stage, and the waves overtake the airplane as its speed decreases to zero. The results for take-off are essentially the same as those for landing, except that the structural waves develop slowly in the early stage, and no obstacle exists on the runway after the take-off of airplane. The additional drag force on an airplane due to the elastic responses of the runway considered in this work was found to be small in magnitude. 相似文献
38.
Toshiyuki?Shigemi Tingyao?ZhuEmail author 《Journal of Marine Science and Technology》2004,9(3):95-108
ClassNK has undertaken wide-ranging basic research covering many aspects related to the safety of ship structures, including design loads, structural analysis, strength assessment of buckling, collapse, and fatigue, and rational corrosion margins to develop new design standards which have transparency and consistency. Among the wide-ranging basic research, this article summarizes the results of extensive work on the design loads used for strength assessments of tanker and bulk carrier structures. The main aim of the research was to develop practical estimation methods of design loads with rational technical backgrounds relating to the actual loads acting on the primary structural members of tankers and bulk carriers. During this study, we proposed the following methodology. Design sea states that closely resemble the actual sea states which are considered to be the most severe for hull structures. Find practical estimation methods for the design sea states by parametric studies using the results of series calculations on representative tankers and bulk carriers. Find practical estimation methods for design regular waves which will result in the same level of stresses as those induced in irregular waves under the design sea states. We also briefly introduced some practical estimation methods for the design loads, such as ship motions, accelerations, hull-girder bending moments, and hydrodynamic pressures that are induced under design regular waves. The findings in this study have been summarized and implemented in the new design standards for tanker and bulk carrier structures.Updated from the Japanese original which won the 2003 SNAJ prize (J Soc Nav Archit Jpn 2002; 191:195–207; 2002; 191:208–220; and 2002; 192:723–733) 相似文献
39.
Nobuyoshi?FukuchiEmail author Changhong?Hu 《Journal of Marine Science and Technology》2004,8(4):177-184
In order to prevent the spread of marine compartment fires, it is necessary to understand the governing factors or characteristics of fire-spread phenomena. We present a pseudofield model approach to this problem. We first described a field model of turbulent heat convection based on a standard k – turbulence model. Two-dimensional numerical simulations of a two-linked compartment fire were carried out in order to predict the turbulent convection flow induced by the heat released from the fire. Then a more complicated fire-spread problem of multilinked compartment fires was analyzed by means of a zone model, in which the amounts of oxygen consumption and gas generation were solved by a gas-balance equations system. The effect of threshold conditions on fire propagation and the effect of the thickness of the heat insulation were investigated with numerical simulations. 相似文献
40.
Shoichi?HaraEmail author Kenji?Yamakawa Kunihiro?Hoshino Kazuhiro?Yukawa 《Journal of Marine Science and Technology》2004,8(3):138-146
A huge floating offshore platform (359m long, 60m wide, and 3m deep) was towed into the Pacific Ocean for a validation experiment for a floating airport. Full-scale measurements of towline tension and the bending strain on the upper-deck were made during towing. The measured bending moment agreed well with numerical calculation without taking the draught and towing speed into consideration. 相似文献