Stakeholder involvement has been a major requirement for effective, efficient, and fair risk governance.Since risk management includes uncertain outcomes that affect different parts of the population to different degr...Stakeholder involvement has been a major requirement for effective, efficient, and fair risk governance.Since risk management includes uncertain outcomes that affect different parts of the population to different degrees it is essential to integrate the knowledge, values, and interests of stakeholders into the risk policy making process.The article provides insights into how to structure and organize stakeholder participation and how to cope with the challenges of complexity, uncertainty, and ambiguity. For each of the three challenges there is a need for specific input from stakeholders. The article describes these requirements and explains the formats that have been tested for providing this input to the risk governance process.展开更多
In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete F...In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete Fourier transform spread orthogonal frequency division multiplexing(DFT-S OFDM) in underwater visible light communication(UVLC) systems. Cascaded post-equalization schemes are suggested to compensate the system impairments. For the first time, a two-level post-equalizer is presented to mitigate the nonlinear effect and improve the system performance of UVLC. The first post-equalization is based on a novel recursive least square Volterra. These modulation formats are all experimentally demonstrated with corresponding digital signal processing(DSP) algorithms. The experimental results show that single carrier modulations including CAP and DFT-S OFDM can outperform OFDM. Our experiment results show that up to 3 Gb/s over a 1.2 m underwater visible light transmission can be achieved by using DFT-S OFDM 64 QAM and CAP-64. The measured bit error rate is well under the hard decision-forward error correction(HD-FEC) threshold of 3.8 × 10^(-3).展开更多
A simple scheme to generate optical quad- rature amplitude modulation （QAM） signals is proposed based on different types of delay interferometers （Dis）. The simulated results show that 16QAM, 64QAM and 256 QAM opt...A simple scheme to generate optical quad- rature amplitude modulation （QAM） signals is proposed based on different types of delay interferometers （Dis）. The simulated results show that 16QAM, 64QAM and 256 QAM optical signals can be generated by 2×2, 3 ×3 and 4×4 DI, respectively, and the outputs of the proposed scheme are similar to those of the conventional schemes. The operation principle is discussed and the transmission properties of the square 16QAM as well as 64QAM signals are analyzed and compared with common approach.展开更多
This paper proposes a model featuring the heterogeneity of consumer preferences and analyzes the multiple equilibrium of retail formats by building a map of the relationships between consumer heterogeneity and retail ...This paper proposes a model featuring the heterogeneity of consumer preferences and analyzes the multiple equilibrium of retail formats by building a map of the relationships between consumer heterogeneity and retail formats. The key questions analyzed in this paper are how the retailer adjusts its combination of marketing elements through repositioning and how innovation in retail formats is implemented to match consumers＇ heterogeneous preferences in a market with consumer search costs. Unlike recent research, our model, by taking different consumer preference structures into account, introduces consumer psychological costs into the Ehrlich-Fisher model and deduces the existence of different retail formats and their multiple equilibriums. We find that consumer heterogeneity, retailers＂ diversified transfer costs and economies of scale are endogenous drivers of prosperous retail formats. Accordingly, diversified retail formats with complementary functions and differentiated services can be described as the horizontal extensions and interface changes of the retailing industry.展开更多
A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed...A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying （DQPSK） payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.展开更多
An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential qu...An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential quadrature phase shift keyed(DQPSK), and non-return-to-zero(NRZ) is proposed. The noise tolerances of different modulation formats are analyzed, and the optimal input power ratio between phase and intensity modulation formats for the best overall receiving performance is investigated under unchanged total input power. Moreover, this scheme can seamlessly coexist with the traditional WDM channel.展开更多
In this paper we analyze the anticompetitive effects of concentration of ownership in auction markets. We compare two different auction formats with uniform price. In the first, the price equals the highest accepted b...In this paper we analyze the anticompetitive effects of concentration of ownership in auction markets. We compare two different auction formats with uniform price. In the first, the price equals the highest accepted bid, whereas in the second the price equals the lowest rejected bid. For the former, and for a two-unit, two-plants, two-firms model, we find an equilibrium where all plants (all firms) bid according to a common bidding function. The concentration of the ownership has the same effect on the bidding behavior as eliminating one plant. However, the expected price is lower than the one expected in such three independent plant scenario. More surprisingly (and special to this 2 × 2 × 2 case), the equilibrium is efficient. In the latter, alternative auction format, firms bids asymmetrically for its two plants. Hence, the equilibrium is inefficient. Also, with this format, we show that the market price may be arbitrarily large. Thus, and contrary to some plausible expectation base in received auction theory, a (sealed-bid) auction format in which the price for a bidder is unrelated to his bid becomes less efficient than one in which the price may coincide with that bidder’s bid, when one admits that several bidders may coordinate (through ownership) their bids. The results add to a literature that favors more winner’s-bid pricing rules.展开更多
We investigate the crosstalk noise, especially the spontaneous Raman scattering, in the optical fiber of a copropagation system between quantum key distribution(QKD) and classical communications. Although many methods...We investigate the crosstalk noise, especially the spontaneous Raman scattering, in the optical fiber of a copropagation system between quantum key distribution(QKD) and classical communications. Although many methods have been proposed, such as increasing the wavelength spacing and narrowband filtering technique, to suppress Raman scattering noise, these methods greatly affect the performance of QKD. One way to solve the obstacle restricting the coexistence is to decrease the classical signal power. Based on the high gain of the gated avalanche photodiode and pulse position modulation, we demonstrate that the co-propagation system works effectively with only a small effect on long-haul fibers, which has great significance for the practical widespread commercialization of QKD.展开更多
In this paper, an investigation is made on compatibility of the video formats TV (625/50/2:1/4:3), EDTV (625/50/1:1/16:9), HDTVint (1250/50/2:1/16:9) and HDTVpro(1250/50/2:1/16:9) in three-dimensional subband coding. ...In this paper, an investigation is made on compatibility of the video formats TV (625/50/2:1/4:3), EDTV (625/50/1:1/16:9), HDTVint (1250/50/2:1/16:9) and HDTVpro(1250/50/2:1/16:9) in three-dimensional subband coding. A hierarchical method is proposed leading to a more reasonable joint solution for the issues of digital transmission evolution and interlace-to-progressive scanning conversion ill the frame work of bit rate compression. Conventional HDTVint with the diamond shaped spectrum is proposed to be replaced by a kind of 'switching'HDTVin signal which consists of three components and motion detection bits (MDB). The first component and the MDB represent TV. The first plus the second component and the MDB represent EDTV.HDTVpro is splitted into switching HDTVint and extra component. The switching threshold and the length of temporal filter banks are discussed. Rearranging the pixels in subbands is recommended. Based on the proposed method, the transmission system can evolve through four steps: TV, EDTV, HDTVint and HDTVpro Results of bit rate compression are also presented. TV, EDTV, HDTVint and HDTVpro are compressed to approximately 40, 80, 128 and 256 Mbit/s respectively. Interlace scanning has drawbacks such as line flicker and line crawling as the eye follows the line structure in the picture. Progressive version switching TV and HDTVint can be reconstructed using one frame memory without the problems of handling temporal-vertical diamond shaped spectra of conventional TV and HDTVint based on a one-frame memory algorithm in the receiver.展开更多
文摘Stakeholder involvement has been a major requirement for effective, efficient, and fair risk governance.Since risk management includes uncertain outcomes that affect different parts of the population to different degrees it is essential to integrate the knowledge, values, and interests of stakeholders into the risk policy making process.The article provides insights into how to structure and organize stakeholder participation and how to cope with the challenges of complexity, uncertainty, and ambiguity. For each of the three challenges there is a need for specific input from stakeholders. The article describes these requirements and explains the formats that have been tested for providing this input to the risk governance process.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61571133)the National Key Research and Development Program of China(No.2017YFB0403603)
文摘In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete Fourier transform spread orthogonal frequency division multiplexing(DFT-S OFDM) in underwater visible light communication(UVLC) systems. Cascaded post-equalization schemes are suggested to compensate the system impairments. For the first time, a two-level post-equalizer is presented to mitigate the nonlinear effect and improve the system performance of UVLC. The first post-equalization is based on a novel recursive least square Volterra. These modulation formats are all experimentally demonstrated with corresponding digital signal processing(DSP) algorithms. The experimental results show that single carrier modulations including CAP and DFT-S OFDM can outperform OFDM. Our experiment results show that up to 3 Gb/s over a 1.2 m underwater visible light transmission can be achieved by using DFT-S OFDM 64 QAM and CAP-64. The measured bit error rate is well under the hard decision-forward error correction(HD-FEC) threshold of 3.8 × 10^(-3).
文摘A simple scheme to generate optical quad- rature amplitude modulation （QAM） signals is proposed based on different types of delay interferometers （Dis）. The simulated results show that 16QAM, 64QAM and 256 QAM optical signals can be generated by 2×2, 3 ×3 and 4×4 DI, respectively, and the outputs of the proposed scheme are similar to those of the conventional schemes. The operation principle is discussed and the transmission properties of the square 16QAM as well as 64QAM signals are analyzed and compared with common approach.
文摘This paper proposes a model featuring the heterogeneity of consumer preferences and analyzes the multiple equilibrium of retail formats by building a map of the relationships between consumer heterogeneity and retail formats. The key questions analyzed in this paper are how the retailer adjusts its combination of marketing elements through repositioning and how innovation in retail formats is implemented to match consumers＇ heterogeneous preferences in a market with consumer search costs. Unlike recent research, our model, by taking different consumer preference structures into account, introduces consumer psychological costs into the Ehrlich-Fisher model and deduces the existence of different retail formats and their multiple equilibriums. We find that consumer heterogeneity, retailers＂ diversified transfer costs and economies of scale are endogenous drivers of prosperous retail formats. Accordingly, diversified retail formats with complementary functions and differentiated services can be described as the horizontal extensions and interface changes of the retailing industry.
基金supported by the National Basic Research Program of China (2003CB314901)the Hi-Tech Research and Development Project of China (2006AA03Z416,2007AA03Z418)+2 种基金the National Natural Science Foundation of China (60576018)the 111 Project (B07005)the Program for Changjiang Scholars and Innovative Research Team in University,MOE
文摘A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying （DQPSK） payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.
基金supported by the National Natural Science Fundation of China(Nos.60932004,61132004,and 61090391)the Program for New Century Excellent Talents in University(No.NCET-10-0520)
文摘An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential quadrature phase shift keyed(DQPSK), and non-return-to-zero(NRZ) is proposed. The noise tolerances of different modulation formats are analyzed, and the optimal input power ratio between phase and intensity modulation formats for the best overall receiving performance is investigated under unchanged total input power. Moreover, this scheme can seamlessly coexist with the traditional WDM channel.
文摘In this paper we analyze the anticompetitive effects of concentration of ownership in auction markets. We compare two different auction formats with uniform price. In the first, the price equals the highest accepted bid, whereas in the second the price equals the lowest rejected bid. For the former, and for a two-unit, two-plants, two-firms model, we find an equilibrium where all plants (all firms) bid according to a common bidding function. The concentration of the ownership has the same effect on the bidding behavior as eliminating one plant. However, the expected price is lower than the one expected in such three independent plant scenario. More surprisingly (and special to this 2 × 2 × 2 case), the equilibrium is efficient. In the latter, alternative auction format, firms bids asymmetrically for its two plants. Hence, the equilibrium is inefficient. Also, with this format, we show that the market price may be arbitrarily large. Thus, and contrary to some plausible expectation base in received auction theory, a (sealed-bid) auction format in which the price for a bidder is unrelated to his bid becomes less efficient than one in which the price may coincide with that bidder’s bid, when one admits that several bidders may coordinate (through ownership) their bids. The results add to a literature that favors more winner’s-bid pricing rules.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61605248 and 61505261)
文摘We investigate the crosstalk noise, especially the spontaneous Raman scattering, in the optical fiber of a copropagation system between quantum key distribution(QKD) and classical communications. Although many methods have been proposed, such as increasing the wavelength spacing and narrowband filtering technique, to suppress Raman scattering noise, these methods greatly affect the performance of QKD. One way to solve the obstacle restricting the coexistence is to decrease the classical signal power. Based on the high gain of the gated avalanche photodiode and pulse position modulation, we demonstrate that the co-propagation system works effectively with only a small effect on long-haul fibers, which has great significance for the practical widespread commercialization of QKD.
文摘In this paper, an investigation is made on compatibility of the video formats TV (625/50/2:1/4:3), EDTV (625/50/1:1/16:9), HDTVint (1250/50/2:1/16:9) and HDTVpro(1250/50/2:1/16:9) in three-dimensional subband coding. A hierarchical method is proposed leading to a more reasonable joint solution for the issues of digital transmission evolution and interlace-to-progressive scanning conversion ill the frame work of bit rate compression. Conventional HDTVint with the diamond shaped spectrum is proposed to be replaced by a kind of 'switching'HDTVin signal which consists of three components and motion detection bits (MDB). The first component and the MDB represent TV. The first plus the second component and the MDB represent EDTV.HDTVpro is splitted into switching HDTVint and extra component. The switching threshold and the length of temporal filter banks are discussed. Rearranging the pixels in subbands is recommended. Based on the proposed method, the transmission system can evolve through four steps: TV, EDTV, HDTVint and HDTVpro Results of bit rate compression are also presented. TV, EDTV, HDTVint and HDTVpro are compressed to approximately 40, 80, 128 and 256 Mbit/s respectively. Interlace scanning has drawbacks such as line flicker and line crawling as the eye follows the line structure in the picture. Progressive version switching TV and HDTVint can be reconstructed using one frame memory without the problems of handling temporal-vertical diamond shaped spectra of conventional TV and HDTVint based on a one-frame memory algorithm in the receiver.
