A novel interleaving based selected mapping （SLM） scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spa...A novel interleaving based selected mapping （SLM） scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spanning only a few bits are used to produce multiple sequences representing the same information, and one of the sequences resulting in the lowest peak-to-average power ratio （PAPR） is selected for transmission. The implementation of the scheme including the structure of the short-span interleaver is illustrated. The performance of this PAPR reduction scheme is investigated by simulations. This scheme exhibits a good PAPR reduction performance, and for signals of high level modulation, such as 16QAM and 64QAM, it approaches the best performance of all SLM schemes. Compared to the conventional interleaving SLM, this short-span interleaving SLM results in a very short time delay, requires very few register units for buffering, and can be easily implemented by hardware.展开更多
In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical j...In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm（ICSA） is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served（FCFS） strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.展开更多
Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak,...Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak, Mt. Seoraksan national park, South Korea from May to August, 2001, breeding population of Siberian rubythroat and the dominant species in breeding area of Siberian rubythroat (Luscinia calliope) were surveyed by line transect method along the ridge in the Daecheongbong peak area. Number of individuals and location of song posts were observed and recorded. According to the survey results, the study area was classified into high, middle and low density areas. Those birds selected the forest area of dominant species for Ermans birch and dwarf Siberian pine as habitat and preferred the shrubs area with the lower height and higher coverage.展开更多
Orthogonal Frequency Division Multiplexing(OFDM)has been used for many wireless communication systems.However,the main drawback of this method is the high Peak-to-Average Power Ratio(PAPR).Selected Mapping(SLM)is a te...Orthogonal Frequency Division Multiplexing(OFDM)has been used for many wireless communication systems.However,the main drawback of this method is the high Peak-to-Average Power Ratio(PAPR).Selected Mapping(SLM)is a technique used for solving the high PAPR problem in OFDM systems.In SLM,the original data sequence is multiplied by a set of predetermined phase sequences and multiple signals with different PAPRs are generated.Then,the one with the lowest PAPR is selected for transmission.The SLM method requires sending of some bits as Side Information(SI)for each data block,which is of critical importance to the receiver for decoding.The SI bits cause a decrease in the bandwidth efficiency;furthermore,incorrect SI detection leads to the loss of an entire data block.In this paper,we exhibit a new SLM technique by using a Multiple Recursive Generator(MRG),a method of generating pseudo random sequences,to send data without explicit SI bits.We show that the proposed technique performs very well in terms of the Bit Error Rate(BER),Probability of detection failure(Pdf)and PAPR reduction.展开更多
文摘A novel interleaving based selected mapping （SLM） scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spanning only a few bits are used to produce multiple sequences representing the same information, and one of the sequences resulting in the lowest peak-to-average power ratio （PAPR） is selected for transmission. The implementation of the scheme including the structure of the short-span interleaver is illustrated. The performance of this PAPR reduction scheme is investigated by simulations. This scheme exhibits a good PAPR reduction performance, and for signals of high level modulation, such as 16QAM and 64QAM, it approaches the best performance of all SLM schemes. Compared to the conventional interleaving SLM, this short-span interleaving SLM results in a very short time delay, requires very few register units for buffering, and can be easily implemented by hardware.
基金Supported by the Basic Scientific Research Projects of the Central University of China(ZXH2010D010)the National Natural Science Foundation of China(60979021/F01)~~
文摘In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm（ICSA） is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served（FCFS） strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.
基金This paper was supported by Korea Science and Engineering Foundation (KOSEF No. 2000-2-51300-002-3).
文摘Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak, Mt. Seoraksan national park, South Korea from May to August, 2001, breeding population of Siberian rubythroat and the dominant species in breeding area of Siberian rubythroat (Luscinia calliope) were surveyed by line transect method along the ridge in the Daecheongbong peak area. Number of individuals and location of song posts were observed and recorded. According to the survey results, the study area was classified into high, middle and low density areas. Those birds selected the forest area of dominant species for Ermans birch and dwarf Siberian pine as habitat and preferred the shrubs area with the lower height and higher coverage.
基金The Iran Telecommunications Research Centre for financial support
文摘Orthogonal Frequency Division Multiplexing(OFDM)has been used for many wireless communication systems.However,the main drawback of this method is the high Peak-to-Average Power Ratio(PAPR).Selected Mapping(SLM)is a technique used for solving the high PAPR problem in OFDM systems.In SLM,the original data sequence is multiplied by a set of predetermined phase sequences and multiple signals with different PAPRs are generated.Then,the one with the lowest PAPR is selected for transmission.The SLM method requires sending of some bits as Side Information(SI)for each data block,which is of critical importance to the receiver for decoding.The SI bits cause a decrease in the bandwidth efficiency;furthermore,incorrect SI detection leads to the loss of an entire data block.In this paper,we exhibit a new SLM technique by using a Multiple Recursive Generator(MRG),a method of generating pseudo random sequences,to send data without explicit SI bits.We show that the proposed technique performs very well in terms of the Bit Error Rate(BER),Probability of detection failure(Pdf)and PAPR reduction.
