In this paper, a Hierarchical Cellular System (HCS) supporting two classes of users with high and low velocity is considered. Based on the analytical model of the bidirectional calloverflow scheme, a new dynamic guard...In this paper, a Hierarchical Cellular System (HCS) supporting two classes of users with high and low velocity is considered. Based on the analytical model of the bidirectional calloverflow scheme, a new dynamic guard channel assignment method is proposed In this method, the number of guard channels in both macrocells and microcells varies in realtime according to the different call traffic load in the HCS, and as a result, the lowest dissatisfaction grade of users is achieved.展开更多
The main purpose of this study is to put forward a reasonable idea of the general protection for Singing Sand Moun- tain and Crescent Moon Spring, a rare and unique desert wonder, and of sustainable tourism developmen...The main purpose of this study is to put forward a reasonable idea of the general protection for Singing Sand Moun- tain and Crescent Moon Spring, a rare and unique desert wonder, and of sustainable tourism development based on the research on the ecological environment around. Methods of documentation, case study and comparison were employed. Finally, aiming at solving the problems of natural environment and those existing after the exploitation of Singing Sand Mountain and Crescent Moon Spring the author puts forward three measures: the com- prehensive treatment for Crescent Moon Spring (broadening re- sources of water and reducing expenditures, checking the de- creasing depth of Crescent Moon Spring, and improving the geo- graphical environment), the general protection envisions for Singing Sand Mountain and Crescent Moon Spring and establish- ing a dynamic monitoring and early-warning system of regional ecosystem.展开更多
基金Supported in part by the National Natural Science Foundation of China(No.69825102)
文摘In this paper, a Hierarchical Cellular System (HCS) supporting two classes of users with high and low velocity is considered. Based on the analytical model of the bidirectional calloverflow scheme, a new dynamic guard channel assignment method is proposed In this method, the number of guard channels in both macrocells and microcells varies in realtime according to the different call traffic load in the HCS, and as a result, the lowest dissatisfaction grade of users is achieved.
文摘The main purpose of this study is to put forward a reasonable idea of the general protection for Singing Sand Moun- tain and Crescent Moon Spring, a rare and unique desert wonder, and of sustainable tourism development based on the research on the ecological environment around. Methods of documentation, case study and comparison were employed. Finally, aiming at solving the problems of natural environment and those existing after the exploitation of Singing Sand Mountain and Crescent Moon Spring the author puts forward three measures: the com- prehensive treatment for Crescent Moon Spring (broadening re- sources of water and reducing expenditures, checking the de- creasing depth of Crescent Moon Spring, and improving the geo- graphical environment), the general protection envisions for Singing Sand Mountain and Crescent Moon Spring and establish- ing a dynamic monitoring and early-warning system of regional ecosystem.
