An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designe...An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.展开更多
Abstract： In this paper, we propose a mecha- nism for multicast data transmission in IEEE 802.16 mesh networks aimed at increasing the throughput by incorporating mini-slot spatial reuse. The proposed mechanism inclu...Abstract： In this paper, we propose a mecha- nism for multicast data transmission in IEEE 802.16 mesh networks aimed at increasing the throughput by incorporating mini-slot spatial reuse. The proposed mechanism includes two novel algorithms： a source-based multicast tree topology construction algorithm followed by an interference-aware multieast scheduling algorithm. The proposed multicast interfer- ence-aware scheduling algorithm can be ap- plied to both source-based and rendez- vous-based multicast tree topologies. Results of our simulation study show that in compari- son to the mechanism used for the IEEE 802.16＇s standard, the proposed multicast tree generation algorithm reduces the number of consumed mini-slots by 64% on average. Moreover, using the proposed interfer- ence-aware scheduling algorithm decreases the number of required mini-slots by a further 22% on average. Therefore, the proposed mul- ticast scheduling mechanism shows a higher throughput than the previous approaches and it is more scalable with respect to increasing the number of multicast groups as well as in- creasing the number of members inside each multicast group.展开更多
The paper presents selected experience of the authors resulting from the optimization tests of double-regulated water turbines. Among the methods for measuring the discharge through the turbine used in such tests, par...The paper presents selected experience of the authors resulting from the optimization tests of double-regulated water turbines. Among the methods for measuring the discharge through the turbine used in such tests, particular attention was paid to index methods allowing to measure the relative discharge through the turbine-the index current meter method and the methods based on measuring the differential pressure between two points properly located at the turbine flow system （i.e., Winter-Kennedy method）. These methods contribute to effective reduction of the cost of optimizing the turbine that is extremely important for small hydropower plants regarding installed capacity. The paper presents selected examples of the optimization tests and experiences that arise from these tests.展开更多
In accordance with a revision of the Containers and Packaging Recycling Law, there is an accelerating trend towards charging for plastic shopping bags （PSBs） in Japan for the purpose of reducing their discharge. The...In accordance with a revision of the Containers and Packaging Recycling Law, there is an accelerating trend towards charging for plastic shopping bags （PSBs） in Japan for the purpose of reducing their discharge. The objectives of this research were to gauge, by means of a questionnaire survey, the opinions of retailers with regard to charging for PSBs, and to consider future directions for reducing the quantity of waste discharged. A questionnaire survey on charging for PSBs was conducted for retail stores in Shizuoka City. The survey was carried out in two phases. The results of the first phase （August to October 2008） showed that supermarkets were generally positive, while conversely other retailer types were negative. The results of the second phase （November to December, 2010）, targeting only supermarkets that had introduced charging after the first survey, showed that there was no major confusion and the shift proceeded relatively smoothly. In addition, the number of customers did not decline on account of charging, and the ratio of shoppers bringing their own reusable ＂eco bags＂ jumped dramatically. On these accounts, it is evident that charging for PSBs is an effective means of reducing usage of PSBs. The authors view it as important for the relevant governmental agencies to work towards promoting charging at retailers and simultaneously repeatedly explaining to consumers the necessity for charging.展开更多
After the 2001 economic crisis, the banking sector restructuring program （BSRP） has been designed for the establishment of a stronger financial framework and the improvement of competition in the Turkish banking sec...After the 2001 economic crisis, the banking sector restructuring program （BSRP） has been designed for the establishment of a stronger financial framework and the improvement of competition in the Turkish banking sector. The program constitutes the policies for solving specific problems such as the mismanaged assets of some banks and the recovery of regulating and supervising of the sector. This study aims to analyze the efficiency and productivity changes in the Turkish banking sector during 2002-2009. During this period the Banking Sector Restructuring Program has been applied. The data envolepment analysis （DEA） is conducted for the efficiency measurement under the production and intermediation approaches and it is observed that the efficiency of banks increased for both approaches. The mean efficiency values for the intermediation approach are higher than the values for the production approach, indicating a better functioning in financial intermediation as compared to their operational performance. The Malmquist index based on the intermediation approach is calculated to determine the productivity of the banking sector. It is observed that the productivity of banks increased during the period and the increase resulted mainly from investments in technology.展开更多
文摘An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.
文摘Abstract： In this paper, we propose a mecha- nism for multicast data transmission in IEEE 802.16 mesh networks aimed at increasing the throughput by incorporating mini-slot spatial reuse. The proposed mechanism includes two novel algorithms： a source-based multicast tree topology construction algorithm followed by an interference-aware multieast scheduling algorithm. The proposed multicast interfer- ence-aware scheduling algorithm can be ap- plied to both source-based and rendez- vous-based multicast tree topologies. Results of our simulation study show that in compari- son to the mechanism used for the IEEE 802.16＇s standard, the proposed multicast tree generation algorithm reduces the number of consumed mini-slots by 64% on average. Moreover, using the proposed interfer- ence-aware scheduling algorithm decreases the number of required mini-slots by a further 22% on average. Therefore, the proposed mul- ticast scheduling mechanism shows a higher throughput than the previous approaches and it is more scalable with respect to increasing the number of multicast groups as well as in- creasing the number of members inside each multicast group.
文摘The paper presents selected experience of the authors resulting from the optimization tests of double-regulated water turbines. Among the methods for measuring the discharge through the turbine used in such tests, particular attention was paid to index methods allowing to measure the relative discharge through the turbine-the index current meter method and the methods based on measuring the differential pressure between two points properly located at the turbine flow system （i.e., Winter-Kennedy method）. These methods contribute to effective reduction of the cost of optimizing the turbine that is extremely important for small hydropower plants regarding installed capacity. The paper presents selected examples of the optimization tests and experiences that arise from these tests.
文摘In accordance with a revision of the Containers and Packaging Recycling Law, there is an accelerating trend towards charging for plastic shopping bags （PSBs） in Japan for the purpose of reducing their discharge. The objectives of this research were to gauge, by means of a questionnaire survey, the opinions of retailers with regard to charging for PSBs, and to consider future directions for reducing the quantity of waste discharged. A questionnaire survey on charging for PSBs was conducted for retail stores in Shizuoka City. The survey was carried out in two phases. The results of the first phase （August to October 2008） showed that supermarkets were generally positive, while conversely other retailer types were negative. The results of the second phase （November to December, 2010）, targeting only supermarkets that had introduced charging after the first survey, showed that there was no major confusion and the shift proceeded relatively smoothly. In addition, the number of customers did not decline on account of charging, and the ratio of shoppers bringing their own reusable ＂eco bags＂ jumped dramatically. On these accounts, it is evident that charging for PSBs is an effective means of reducing usage of PSBs. The authors view it as important for the relevant governmental agencies to work towards promoting charging at retailers and simultaneously repeatedly explaining to consumers the necessity for charging.
文摘After the 2001 economic crisis, the banking sector restructuring program （BSRP） has been designed for the establishment of a stronger financial framework and the improvement of competition in the Turkish banking sector. The program constitutes the policies for solving specific problems such as the mismanaged assets of some banks and the recovery of regulating and supervising of the sector. This study aims to analyze the efficiency and productivity changes in the Turkish banking sector during 2002-2009. During this period the Banking Sector Restructuring Program has been applied. The data envolepment analysis （DEA） is conducted for the efficiency measurement under the production and intermediation approaches and it is observed that the efficiency of banks increased for both approaches. The mean efficiency values for the intermediation approach are higher than the values for the production approach, indicating a better functioning in financial intermediation as compared to their operational performance. The Malmquist index based on the intermediation approach is calculated to determine the productivity of the banking sector. It is observed that the productivity of banks increased during the period and the increase resulted mainly from investments in technology.
